Wafer cleaning method and wafer cleaning apparatus

Abstract

This invention provides a wafer cleaning method and a wafer cleaning apparatus. The wafer cleaning method includes the following steps: placing a wafer on a support stage; controlling the movement of the support stage to maintain a certain distance between the wafer and the spray channels; transmitting cleaning fluid to a nozzle having a plurality of spray channels; controlling an ultrasonic generator to send ultrasonic waves toward the spray channels, so that the cleaning fluid is sprayed onto the wafer surface in the form of droplets through the spray channels; wherein the resistance of the cleaning fluid is less than or equal to 1 MΩ. This invention can effectively remove adhering particles from the wafer surface. The reasonable nozzle distance and droplet spraying method also help to avoid the risk of physical impact damage to circuit patterns by droplets, improve cleaning efficiency and quality, and reduce the damage to circuit patterns caused by electrostatic accumulation, thereby improving wafer yield and reliability.

Description

Technical Field

[0001] This invention relates to the field of semiconductor manufacturing technology, and in particular to wafer cleaning methods and wafer cleaning apparatus. Background Technology

[0002] With the continuous development of semiconductor technology, the effective cleaning of particles adhering to the surface of silicon wafers has become a crucial step in chip manufacturing. Especially for chips manufactured using processes above 28nm, it is necessary to ensure a high particle removal rate while preventing damage to the intricate circuit patterns on the silicon wafer surface.

[0003] Currently, common cleaning nozzles are mainly single-fluid nozzles and two-fluid nozzles. However, single-fluid nozzles, limited by their droplet generation principle, produce a high proportion of millimeter-sized droplets. These larger droplets are not effective in physically removing particles adhering to the silicon wafer surface and can easily damage circuit patterns. Compared to single-fluid nozzles, two-fluid nozzles can produce smaller droplets, but the droplet velocity and diameter distribution range is still relatively wide, making it difficult to avoid damaging circuit patterns.

[0004] Furthermore, regardless of whether it's a single-fluid or two-fluid nozzle, when using high-speed fluids, the friction between the high-speed liquid flow and the nozzle body generates static electricity accumulation, which has a significant destructive effect on circuit patterns. Piezoelectric transducers face similar problems to two-fluid nozzles, and piezoelectric transducers in direct contact with the liquid may also introduce new charge contamination. These shortcomings of existing technologies mean that during wafer cleaning, the static electricity accumulation generated by the friction between the high-speed liquid flow and the nozzle body damages the circuit patterns on the wafer surface. Summary of the Invention

[0005] This invention provides a wafer cleaning method and a wafer cleaning apparatus to solve the technical problem mentioned in the background art, which is that the static electricity accumulation caused by the friction between the high-speed liquid flow and the nozzle body damages the circuit patterns on the wafer surface.

[0006] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows: This application provides a wafer cleaning method, including the following steps: Place the wafer on the support stage; Control the movement of the support stage to maintain a certain distance between the wafer and the jet channel; The cleaning fluid is delivered to a nozzle, which has several spray channels; The ultrasonic generator is controlled to send ultrasonic waves toward the jet channel, so that the cleaning fluid is sprayed onto the wafer surface in the form of droplets through the jet channel. The resistance of the cleaning fluid is less than or equal to 1 MΩ.

[0007] Optionally, before the cleaning fluid is transferred to the nozzle, the following steps are included: Control the movement of the support stage to maintain a distance of 3-50 mm between the wafer and the jet channel; and / or, A solute is added to liquid water or liquid hydrogen peroxide to form a solution; The solution is ionized to obtain the cleaning solution containing ions; The temperature of the cleaning solution is controlled between 10 and 80°C.

[0008] Optionally, controlling the ultrasonic generator to send ultrasonic waves toward the jet channel, so that the cleaning fluid is sprayed onto the wafer surface in the form of droplets through the jet channel, includes: The jet velocity of the cleaning fluid in the jet channel is controlled to be between 15 and 80 m / s; wherein the equivalent diameter of the jet channel is 3 to 20 μm. The driving ultrasonic frequency of the piezoelectric element in the ultrasonic generator is adjusted to 0~3MHz so that the diameter of the droplets sprayed onto the wafer surface is 10~40μm.

[0009] Optionally, the process of delivering the cleaning fluid to the nozzle includes: The flow rate of the cleaning solution should be controlled at 10~200mL / min; The pressure in the conveying channel is controlled between 0.1 and 15 MPa.

[0010] This application also provides a wafer cleaning apparatus capable of implementing the above-described wafer cleaning method, comprising: A support platform is used to support wafers; A nozzle is spaced apart from the support platform. The nozzle has a conveying channel and several spray channels. One end of the conveying channel is a liquid inlet and the other end is a liquid outlet. The several spray channels are connected to the conveying channel and are used to spray droplets toward the support platform. A liquid inlet section is connected to the liquid inlet port, and the liquid inlet section is used to connect to an external liquid supply source; The liquid outlet section is connected to the liquid outlet, which is used to connect to an external liquid supply source; An ultrasonic generator is located on the side of the nozzle away from the support platform; The controller is electrically connected to the ultrasonic generator.

[0011] Optionally, the conveying channel is provided with a plurality of injection holes spaced apart along its axial direction; Each of the jet channels is connected to a corresponding jet hole; The equivalent diameter of the jet channel is 3μm to 20μm.

[0012] Optionally, the liquid inlet is equipped with a metering pump, which is electrically connected to the controller; In operation, the controller controls the metering pump to operate so that the flow rate of the cleaning solution is 10~200mL / min, the pressure of the delivery channel is 0.1~15MPa, and the jet velocity of the jet channel is 15~80m / s.

[0013] Optionally, the ultrasonic generator includes a piezoelectric element, the working area of ​​which completely covers the conveying channel; In operation, the controller controls the driving ultrasonic frequency range of the piezoelectric element to be 0~3MHz.

[0014] Optionally, the liquid supply source is equipped with a heater and a temperature detector, and the heater and the temperature detector are electrically connected to the controller; The temperature detector is used to detect the temperature of the cleaning fluid; The heater is used to heat the cleaning fluid to maintain its temperature between 10 and 80°C.

[0015] Optionally, the jet channel includes a first variable diameter section and a second variable diameter section, wherein the diameter of the first variable diameter section is larger than the diameter of the second variable diameter section, and the second variable diameter section is located on both sides of the first variable diameter section.

[0016] The beneficial effects of the wafer cleaning method and wafer cleaning apparatus provided in this application are as follows: 1. By controlling the distance between the nozzle and the wafer surface and spraying the cleaning solution in droplet form, it is possible to effectively remove the adhering particles on the wafer surface. A reasonable nozzle distance and droplet spraying method also help to avoid the risk of physical impact damage to the circuit pattern by the droplets, thereby improving cleaning efficiency and quality.

[0017] 2. The cleaning solution provided in this application has a resistance value of less than or equal to 1MΩ. By using this cleaning solution, the damage to circuit patterns caused by static electricity accumulation can be reduced, thereby improving the yield and reliability of the wafer. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 A schematic flowchart of the wafer cleaning method provided in this application; Figure 2This is a schematic diagram of the structure of the wafer cleaning apparatus provided in the embodiments of this application; Figure 3 A schematic diagram illustrating the trend of the driving ultrasonic frequency of the piezoelectric element in the ultrasonic generator and the corresponding droplet diameter in the embodiments provided in this application; Figure 4 A cross-sectional view along the axial direction of the jet flow channel provided in the embodiment of this application.

[0020] Icons: 10-Liquid inlet; 20-Liquid outlet; 30-Nozzle; 31-Conveying channel; 32-Jet channel; 321-First diameter changing section; 322-Second diameter changing section; 40-Ultrasonic generator; 50-Supporting platform.

[0021] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0023] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of this invention are only used to explain the relative positional relationship and movement of the components in a specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0024] In this application, unless otherwise expressly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0025] Furthermore, if the embodiments of this application involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the meaning of "and / or" throughout the text includes three parallel solutions; for example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

[0026] In existing wafer cleaning processes, the static electricity generated by the friction between the high-speed liquid stream and the jet channel body can damage the circuit patterns on the wafer surface, thereby harming the wafer. To address these problems, embodiments of this application provide the following technical solutions to overcome them.

[0027] Please refer to Figure 1 and Figure 2 As shown in the figure, this application provides a wafer cleaning method, including the following steps: S100: Place the wafer on the support stage 50.

[0028] In this step, a lifting mechanism is provided below the support stage 50, which can drive the wafer to move up and down. Furthermore, the support stage 50 can also rotate the wafer to improve the cleaning effect.

[0029] S200: Control the movement of the support stage 50 to maintain a certain distance between the wafer and the jet channel 32.

[0030] In this step, the carrier stage 50 can be moved to keep the distance between the wafer and the jet channel 32 at 25mm.

[0031] S300: The cleaning fluid is transferred to the nozzle 30, which has a plurality of spray channels 32.

[0032] S400: Control the ultrasonic generator to send ultrasonic waves toward the jet channel 32, so that the cleaning fluid is sprayed onto the wafer surface in the form of droplets through the jet channel 32. The resistance of the cleaning fluid is less than or equal to 1 MΩ.

[0033] In this embodiment, by controlling the movement of the support platform 50, the distance between the nozzle 30 and the wafer surface is kept between 3mm and 50mm. This ensures that the cleaning fluid has sufficient impact force to remove particles when sprayed onto the wafer surface, while also preventing the droplets from damaging the circuit patterns on the wafer surface due to excessive distance.

[0034] It should be noted that when the nozzle 30 is too close, the impact of the droplets may damage the delicate circuit patterns; when the nozzle 30 is too far away, the impact of the droplets will be weakened, affecting the particle removal effect.

[0035] Furthermore, spraying the cleaning solution into droplets onto the wafer surface provides a more concentrated impact force compared to a continuous flow of liquid, effectively removing particles adhering to the wafer surface. Simultaneously, droplet spraying allows for better control of the cleaning solution's dosage and coverage area, reducing over-cleaning and damage to the wafer surface.

[0036] Furthermore, the resistance of the cleaning solution in this embodiment is less than or equal to 1 MΩ, giving it a certain degree of conductivity. When the cleaning solution is sprayed onto the wafer surface, the conductive solution can promptly conduct away static electricity from the wafer surface, preventing static accumulation from damaging the circuit patterns on the wafer surface and thus improving wafer yield and reliability. This is because prolonged accumulation of static electricity on the wafer surface can lead to charge buildup in the circuit patterns, causing problems such as short circuits and electromigration, affecting wafer performance and quality.

[0037] In some embodiments, the process of delivering the cleaning fluid to the nozzle 30 includes: A solute is added to liquid water or liquid hydrogen peroxide to form a solution. The solute dissolves in the liquid and undergoes self-ionization, yielding a cleaning solution containing free ions. Finally, the temperature of the cleaning solution is controlled at 10~80℃ for preservation.

[0038] Specifically, adding solutes to liquid water or liquid hydrogen peroxide can alter the fundamental chemical properties of the cleaning solution. For example, adding solutes that generate specific ions can adjust the pH, redox capacity, and other properties of the cleaning solution, making it more suitable for removing specific types of particles. Furthermore, through ionization, the solute in the solution decomposes into ions. These ions can play various roles during the cleaning process, such as adsorbing charged particles through electrostatic interactions and reacting with chemical groups on the particle surface, thereby improving particle removal efficiency. Simultaneously, the presence of ions can increase the conductivity of the cleaning solution, helping to reduce static electricity buildup.

[0039] In this embodiment, the solute introduced into the liquid water is carbon dioxide, which partially dissolves in the liquid water to form a carbonic acid solution. The carbonic acid solution is further ionized to obtain a cleaning solution containing hydrogen ions and carbonate ions. The hydrogen ions make the cleaning solution weakly acidic, which helps remove metal oxide particles; the carbonate ions can form soluble or insoluble compounds with certain metal ions, thereby peeling particles containing metal ions from the wafer surface.

[0040] In other embodiments, ammonia gas can be introduced into liquid hydrogen peroxide, and the ammonia gas dissolves in the hydrogen peroxide to form an ammonia monohydrate solution. The ammonia monohydrate solution ionizes to obtain a cleaning solution containing hydrogen ions and ammonium ions. The strong oxidizing properties of hydrogen peroxide itself can decompose organic contaminants, while the ammonium ions can electrostatically adsorb onto the negatively charged particle surface, making it easier for the particles to be carried away from the wafer surface by the cleaning solution.

[0041] Understandably, cleaning solutions containing ions can effectively dissipate static electricity, reducing the risk of damage to the circuit patterns on the wafer surface, thereby protecting the delicate circuit structures on the wafer and improving wafer yield. Furthermore, different solutes and ionization conditions can be selected according to different cleaning needs, allowing the cleaning solution to adapt to various process requirements and wafer characteristics, thus improving the flexibility and versatility of the cleaning process.

[0042] More importantly, maintaining the temperature of the cleaning solution at 10~80℃ during storage ensures the performance of the cleaning solution and thus improves the cleaning effect.

[0043] In one embodiment, the control of the ultrasonic generator to send ultrasonic waves toward the jet channel 32, so that the cleaning fluid is sprayed onto the wafer surface in the form of droplets through the jet channel 32, includes: The jet velocity of the jet channel 32 is controlled to be between 15 and 80 m / s; wherein the equivalent diameter of the jet channel 32 is between 3 and 20 μm.

[0044] The driving ultrasonic frequency of the piezoelectric element in the ultrasonic generator is adjusted to 0~3MHz so that the diameter of the droplets sprayed onto the wafer surface is 10~40μm.

[0045] In this embodiment, high-frequency mechanical vibration is generated by the piezoelectric element of the ultrasonic generator 40. This vibration is transmitted to the nozzle 30 and its internal jet channel 32, applying periodic forced disturbance to the cleaning liquid column that is about to be ejected. This disturbance at a specific frequency will cause the liquid column to break at a preset wavelength, forming droplets with controllable droplet diameter.

[0046] Combination Figure 3As shown, specifically, under the premise that the equivalent diameter of the jet channel 32 inside the nozzle 30 is set to 3~20μm and the jet velocity of the jet channel 32 is controlled to be 15~80m / s, the diameter of the droplets generated by the breakage of the liquid column can be precisely controlled by adjusting the driving ultrasonic frequency of the piezoelectric element to the range of 0~3MHz, so that it is stably maintained in the target range of 10μm~40μm.

[0047] It should be noted that controlling the droplet diameter within the range of 10μm to 40μm ensures the droplets possess appropriate impact force. When the droplets are sprayed onto the wafer surface, smaller droplets can more precisely impact particles, and due to their smaller mass, the risk of damage to the circuit patterns on the wafer surface is reduced. Larger droplets (close to 40μm) are suitable for removing larger or more stubborn particles, while smaller droplets (close to 10μm) can penetrate the tiny gaps on the wafer surface, removing hidden particles and improving the cleaning effect.

[0048] Therefore, controlling the droplet diameter within an appropriate range can effectively remove particles of different sizes and types, including stubborn physical particles and tiny particles hidden in crevices, thereby improving the cleaning effect. Furthermore, a moderately sized droplet can reduce the impact on the circuit patterns on the wafer surface while ensuring cleaning effectiveness, minimizing the risk of physical damage caused by excessively large droplets and maintaining the integrity and functionality of the wafer.

[0049] Furthermore, setting the jet velocity within the range of 15 m / s to 80 m / s ensures that the droplets possess sufficient impact force to remove particles from the wafer surface without damaging the circuit patterns. This is because setting the jet velocity below 15 m / s results in insufficient droplet impact force, making it difficult to effectively remove stubborn particles from the wafer surface. Conversely, setting the jet velocity above 80 m / s results in excessive droplet impact force, which can damage the circuit patterns on the wafer surface.

[0050] In this embodiment, the jet velocity is controlled by adjusting the speed of the drive motor of the metering pump in the liquid inlet 10. The metering pump can be precisely controlled in speed. The metering pump can be a gear pump or a plunger pump driven by a servo motor, and its discharge flow rate is proportional to the motor speed. Under the condition that the total cross-sectional area of ​​the jet channel 32 is fixed, the jet velocity of the cleaning fluid is directly determined by the volume of liquid passing through that cross-section per unit time, that is, it uniquely corresponds to the discharge flow rate of the pump. Therefore, by setting the pump speed by outputting a specific motor drive signal by the control module, the corresponding discharge flow rate can be obtained, so that the cleaning fluid flowing through all jet channels 32 obtains a consistent jet linear velocity. By pre-establishing the mapping relationship or calculation formula between the pump speed and the jet velocity, the flow rate can be precisely controlled within any target value in the range of 15m / s to 80m / s, ensuring that the droplet impact force is sufficient to remove particles without damaging the wafer pattern.

[0051] In one embodiment, the step of transferring the cleaning fluid to the nozzle 30 includes: controlling the flow rate of the cleaning fluid to be 10~200 mL / min; and controlling the pressure of the delivery channel 31 to be 0.1~15 MPa.

[0052] It should be noted that, according to fluid mechanics principles, the pressure within the delivery channel 31, along the entire path of the cleaning fluid from the outlet of the metering pump through the delivery channel 31 to its ejection from the ejection channel 32, is determined by both the output flow rate of the metering pump and the fluid resistance of the entire internal structure of the nozzle 30. When the internal structure of the nozzle 30 is fixed, its flow resistance characteristic is constant. At this time, the pressure in the delivery channel 31 is directly proportional to the output flow rate of the metering pump. Therefore, by adjusting the motor speed of the metering pump to regulate its discharge flow rate, the pressure in the delivery channel 31 can be controlled. This invention uses a controller to adjust the operating point of the metering pump according to a preset pressure-speed correspondence. By controlling the delivery flow rate of the cleaning fluid to 10~200mL / min, the pressure in the delivery channel 31 can be stably maintained at any desired value within the range of 0.1~15MPa, ensuring that the cleaning fluid obtains suitable jet kinetic energy.

[0053] In this embodiment, by controlling the flow rate of the cleaning fluid to 10~200mL / min, the pressure of the delivery channel 31 is kept within the range of 0.1MPa to 15MPa, thereby further ensuring the cleaning effect on the wafer.

[0054] This application also provides a wafer cleaning apparatus, see reference. Figure 2 As shown, the system includes a liquid inlet 10, a liquid outlet 20, a nozzle 30, an ultrasonic generator 40, a support platform 50, and a controller. The support platform 50 is used to support the wafer, and a lifting mechanism is located below the support platform 50 to raise and lower it. The nozzle 30 is spaced apart from the support platform 50, specifically positioned above it. The nozzle 30 has a conveying channel 31 and several jetting channels 32. One end of the conveying channel 31 is a liquid inlet, and the other end is a liquid outlet. The several jetting channels 32 are connected to the conveying channel 31 and are used to spray droplets towards the support platform 50. The liquid inlet 10 is connected to the liquid inlet and is used to connect to an external liquid supply source. The liquid outlet 20 is connected to the liquid outlet and is used to connect to an external liquid supply source to achieve liquid circulation. The ultrasonic generator 40 is attached to the side of the nozzle 30 away from the support platform 50, and the controller is electrically connected to the ultrasonic generator 40 and the lifting mechanism.

[0055] In operation, the wafer is pre-placed on the support stage 50, and the controller moves the support stage 50 until it maintains a certain distance from the jet channel 32. Then, the liquid supply source introduces the cleaning fluid into the nozzle 30 through the inlet section 10, and the outlet section 20 transfers a portion of the cleaning fluid from the nozzle 30 back to the supply source to achieve partial liquid circulation. During this process, the controller controls the ultrasonic generator 40 to send ultrasonic waves towards the jet channel 32, causing the cleaning fluid to be sprayed onto the wafer surface in the form of droplets through the jet channel 32. The resistance of the cleaning fluid stored in the supply source is less than or equal to 1 MΩ.

[0056] Understandably, the ultrasonic generator 40 induces the cleaning fluid to form uniform droplets, which, combined with the precise control of the nozzle 30, can effectively remove adhering particles from the wafer surface, improving the particle removal rate. By precisely controlling the movement of the nozzle 30 and droplet formation, damage to the circuit patterns on the wafer surface is avoided, maintaining the wafer's integrity and functionality. It is compatible with cleaning fluids of different properties, and the cleaning process can be optimized according to wafer characteristics and contaminant types, enhancing the flexibility and adaptability of the cleaning process.

[0057] In one embodiment, the conveying channel 31 is provided with a plurality of injection holes spaced apart along its axial direction; each injection channel 32 is connected to a corresponding injection hole. The equivalent diameter of the injection channel 32 is 3μm to 20μm.

[0058] In this embodiment, the delivery channel 31 is a small-diameter delivery channel. The delivery channel 31 serves as a transmission channel for the cleaning fluid inside the nozzle 30, uniformly distributing the cleaning fluid introduced by the inlet section 10 into each spray channel 32. This ensures that the cleaning fluid reaches each spray channel 32 at a stable and uniform flow rate, avoiding differences in cleaning effect caused by uneven flow. Several spray channels 32 are evenly arrayed and oriented towards the support platform 50, ensuring that the cleaning fluid droplets can uniformly cover the entire wafer surface, improving the uniformity and consistency of the cleaning process.

[0059] Furthermore, by setting the equivalent diameter of the jet channel 32 to 3μm~20μm, the diameter of the droplets sprayed onto the wafer surface is 10~40μm, which improves the cleaning effect while reducing the risk of damage to the circuit patterns on the wafer surface.

[0060] In one embodiment, the liquid inlet 10 is equipped with a metering pump, which is electrically connected to the controller.

[0061] In operation, the controller controls the metering pump to operate so that the flow rate of the cleaning solution is 10~200mL / min, the pressure of the delivery channel 31 is 0.1~15MPa, and the jet velocity of the jet channel 32 is 15~80m / s.

[0062] In this embodiment, as described above, the pressure within the delivery channel 31 of the cleaning fluid, flowing from the outlet of the metering pump through the delivery channel 31 and exiting through the spray channel 32, is determined by the output flow rate of the metering pump and the fluid resistance of the entire internal structure of the nozzle 30. When the internal structure of the nozzle 30 is fixed, its flow resistance characteristic is constant. At this time, the pressure of the delivery channel 31 is proportional to the output flow rate of the metering pump. Therefore, by adjusting the motor speed of the metering pump to adjust its discharge flow rate, the pressure of the delivery channel 31 can be controlled. This invention adjusts the operating point of the metering pump according to a preset pressure-speed correspondence using a controller. By controlling the delivery flow rate of the cleaning fluid to 10~200mL / min, the pressure of the delivery channel 31 can be stably maintained at any desired value within 0.1~15MPa, and the spray velocity of the spray channel 32 can be controlled to be 15~80m / s, ensuring that the cleaning fluid obtains suitable spray kinetic energy.

[0063] In one embodiment, the ultrasonic generator 40 includes a piezoelectric element attached to the side of the nozzle 30 away from the support platform 50, and the working area of ​​the piezoelectric element completely covers the jet channel 32; the controller controls the driving ultrasonic frequency generated by the piezoelectric element to be between 0 and 3 MHz.

[0064] In this embodiment, the piezoelectric element is attached to the side of the nozzle 30 facing away from the support platform 50, and the working area completely covers the jet channel 32. This arrangement ensures that the ultrasonic waves can act uniformly on all jet channels 32, so that the cleaning fluid in each jet channel 32 is subjected to the same ultrasonic vibration effect, thereby ensuring the uniformity of droplet formation.

[0065] In some embodiments, the liquid supply source is equipped with a heater and a temperature detector, which are electrically connected to the controller; the temperature detector is used to detect the temperature of the cleaning liquid; the heater is used to heat the cleaning liquid to maintain its temperature at 10~80°C.

[0066] In this embodiment, by maintaining the temperature of the cleaning fluid in the liquid supply source at 10~80℃, the performance of the cleaning fluid is ensured, thereby improving the cleaning effect on the wafer.

[0067] refer to Figure 4As shown, in some embodiments, the jet channel 32 includes a first variable diameter section 321 and a second variable diameter section 322, wherein the diameter of the first variable diameter section 321 is larger than the diameter of the second variable diameter section 322, and the second variable diameter section 322 is located on both sides of the first variable diameter section 321.

[0068] In this embodiment, the length of the jet channel 32 is λ. Since the jet channel 32 includes a first variable diameter section 321 and a second variable diameter section 322, and the diameter of the first variable diameter section 321 is larger than the diameter of the second variable diameter section 322, with the second variable diameter section 322 located on both sides of the first variable diameter section 321, when the ultrasonic generator sends ultrasonic waves to the jet channel 32, it will cause the liquid column to break into droplets within the jet channel 32.

[0069] The above description is merely a specific implementation of the embodiments of this application, but the protection scope of the embodiments of this application is not limited thereto. Any changes or substitutions within the technical scope disclosed in the embodiments of this application should be covered within the protection scope of the embodiments of this application. Therefore, the protection scope of the embodiments of this application should be determined by the protection scope of the claims.

Claims

1. A wafer cleaning method, characterized in that, Includes the following steps: Place the wafer on the support stage; Control the movement of the support stage to maintain a certain distance between the wafer and the jet channel; The cleaning fluid is delivered to a nozzle, which has several spray channels; The ultrasonic generator is controlled to send ultrasonic waves toward the jet channel, so that the cleaning fluid is sprayed onto the wafer surface in the form of droplets through the jet channel. The resistance of the cleaning fluid is less than or equal to 1 MΩ.

2. The wafer cleaning method according to claim 1, characterized in that, Before the cleaning fluid is transferred to the nozzle, the process includes: Control the movement of the support stage to maintain a distance of 3-50 mm between the wafer and the jet channel; and / or, A solute is added to liquid water or liquid hydrogen peroxide to form a solution; The solution is ionized to obtain the cleaning solution containing ions; The temperature of the cleaning solution is controlled between 10 and 80°C.

3. The wafer cleaning method according to claim 1, characterized in that, The control of the ultrasonic generator to send ultrasonic waves toward the jet channel, so that the cleaning fluid is sprayed onto the wafer surface in the form of droplets through the jet channel, includes: The jet velocity of the cleaning fluid in the jet channel is controlled to be between 15 and 80 m / s; wherein the equivalent diameter of the jet channel is 3 to 20 μm. The driving ultrasonic frequency of the piezoelectric element in the ultrasonic generator is adjusted to 0~3MHz so that the diameter of the droplets sprayed onto the wafer surface is 10~40μm.

4. The wafer cleaning method according to claim 1, characterized in that, The process of transferring the cleaning fluid to the nozzle includes: The flow rate of the cleaning solution should be controlled at 10~200mL / min; The pressure in the conveying channel is controlled between 0.1 and 15 MPa.

5. A wafer cleaning apparatus, characterized in that, The wafer cleaning method as described in any one of claims 1-5 can be implemented, wherein the wafer cleaning apparatus comprises: A support platform is used to support wafers; A nozzle is spaced apart from the support platform. The nozzle has a conveying channel and several spray channels. One end of the conveying channel is a liquid inlet and the other end is a liquid outlet. The several spray channels are connected to the conveying channel and are used to spray droplets toward the support platform. A liquid inlet section is connected to the liquid inlet port, and the liquid inlet section is used to connect to an external liquid supply source; The liquid outlet section is connected to the liquid outlet, which is used to connect to an external liquid supply source; An ultrasonic generator is located on the side of the nozzle away from the support platform; The controller is electrically connected to the ultrasonic generator.

6. The wafer cleaning apparatus according to claim 5, characterized in that, The conveying channel is provided with a plurality of injection holes spaced apart along its axial direction; Each of the jet channels is connected to a corresponding jet hole; The equivalent diameter of the jet channel is 3μm to 20μm.

7. The wafer cleaning apparatus according to claim 5, characterized in that, The liquid inlet section is equipped with a metering pump, which is electrically connected to the controller. In operation, the controller controls the metering pump to operate so that the flow rate of the cleaning solution is 10~200mL / min, the pressure of the delivery channel is 0.1~15MPa, and the jet velocity of the jet channel is 15~80m / s.

8. The wafer cleaning apparatus according to claim 5, characterized in that, The ultrasonic generator includes a piezoelectric element, the working area of ​​which completely covers the conveying channel; In operation, the controller controls the driving ultrasonic frequency range of the piezoelectric element to be 0~3MHz.

9. The wafer cleaning apparatus according to claim 5, characterized in that, The liquid supply source is equipped with a heater and a temperature detector, and the heater and the temperature detector are electrically connected to the controller; The temperature detector is used to detect the temperature of the cleaning fluid; The heater is used to heat the cleaning fluid to maintain its temperature between 10 and 80°C.

10. The wafer cleaning apparatus according to claim 6, characterized in that, The jet channel includes a first variable diameter section and a second variable diameter section, wherein the diameter of the first variable diameter section is larger than the diameter of the second variable diameter section, and the second variable diameter section is located on both sides of the first variable diameter section.

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