Method and apparatus for cleaning substrates using high temperature chemicals and ultrasonic devices

Abstract

The application discloses a high-temperature chemical solution supply system for cleaning a substrate. The system comprises a solution tank for containing a chemical solution; a first pump, an inlet of the first pump being connected to the solution tank, and an outlet of the first pump being connected to a buffer tank; the buffer tank comprising a tank body, an exhaust pipe and a needle valve, one end of the exhaust pipe being connected to the tank body, the other end of the exhaust pipe being connected to the solution tank, and the needle valve being installed on the exhaust pipe and used for adjusting the pressure in the buffer tank; and a second pump, an inlet of the second pump being connected to the buffer tank, and an outlet of the second pump being connected to a cleaning cavity for cleaning the substrate. When the second pump is in an open state, the first pump and the needle valve are also in the open state, the pressure in the buffer tank is adjusted by the needle valve and the first pump, and the chemical solution in the buffer tank is pressed into the inlet of the second pump. The application further provides a substrate cleaning device comprising the high-temperature chemical solution supply system and an ultrasonic / megasonic device. The application further provides a method for cleaning a substrate.

Description

[0001] This application is a divisional application of the invention patent application filed on December 9, 2015, with application number 201580085060.0 and invention title "Method and Apparatus for Cleaning Substrates Using High-Temperature Chemicals and Ultrasonic Devices". Technical Field

[0002] This invention relates to substrate cleaning methods and apparatus, and more particularly to reducing bubbles in high-temperature chemical solutions such as SC1, and reducing bubbles generated or accumulated during substrate cleaning in a single-wafer cleaning machine equipped with ultrasonic devices when supplying high-temperature chemical solutions to the substrate. Background Technology

[0003] In semiconductor device manufacturing, particles on the substrate surface need to be removed or cleaned before proceeding to the next process. For example, after CMP (chemical mechanical planarization), polishing slurry and residues on the substrate surface are very difficult to remove. High-temperature sulfuric acid (SPM) is typically used to remove these particles; however, sulfuric acid is not only difficult to handle safely, but its waste disposal is also very expensive. Hot SC1 (including hydrogen peroxide, ammonia, and water) is a good alternative to hot sulfuric acid, but to effectively remove particles, the SC1 temperature needs to be heated to above 80°C.

[0004] When SC1 reaches such high temperatures, the hydrogen peroxide and ammonia in the SC1 chemicals easily decompose into oxygen and ammonia through low-pressure suction, mechanical agitation, and heating. This mixture of SC1 bubbles can easily cause pumps, heaters, flow meters, and ultrasonic equipment to malfunction during the cleaning process.

[0005] Therefore, a better method is needed to control bubbles in high-temperature chemical solutions when ultrasonic energy is applied to the substrate during mixing, heating, transporting, and final cleaning. Summary of the Invention

[0006] This invention proposes a high-temperature chemical solution supply system for cleaning substrates. The system includes: a solution tank for containing a chemical solution; a first pump, the inlet of which is connected to the solution tank, and the outlet of which is connected to a buffer tank; a buffer tank including a tank body, an exhaust pipe, and a needle valve, one end of the exhaust pipe being connected to the tank body and the other end to the solution tank, and the needle valve being mounted on the exhaust pipe for regulating the pressure within the buffer tank; and a second pump, the inlet of which is connected to the buffer tank, and the outlet of which is connected to a cleaning chamber for cleaning the substrate. When the second pump is in the open state, the first pump and the needle valve are also in the open state. The pressure within the buffer tank is regulated by the needle valve and the first pump, causing the chemical solution in the buffer tank to be forced into the inlet of the second pump.

[0007] This invention also proposes an apparatus for cleaning a substrate. The apparatus includes a solution tank for containing a chemical solution; a first pump, the inlet of which is connected to the solution tank, and the outlet of which is connected to a buffer tank; a buffer tank including a tank body, an exhaust pipe, and a needle valve, one end of which is connected to the tank body and the other end to the solution tank, and the needle valve mounted on the exhaust pipe for adjusting the pressure within the buffer tank; and a second pump, the inlet of which is connected to the buffer tank, and the outlet of which is connected to a cleaning chamber for cleaning the substrate, wherein when the second pump is in the open state, the first pump and the needle valve are also in the open state, and the pressure within the buffer tank is adjusted by the needle valve and the first pump to force the chemical solution in the buffer tank into the inlet of the second pump; a substrate chuck for carrying the substrate; a rotary drive device connected to the substrate chuck and driving the substrate chuck to rotate; a nozzle for spraying a high-temperature chemical solution or deionized water onto the substrate surface; an ultrasonic / megason device positioned close to the substrate, with a gap between the substrate and the ultrasonic / megason device; and a vertical actuator for driving the ultrasonic / megason device to rise or fall to change the gap between the substrate and the ultrasonic / megason device.

[0008] This invention proposes a method for cleaning a substrate, comprising: rotating the substrate; spraying deionized water onto the substrate surface to pre-wet the substrate surface; spraying a high-temperature chemical solution onto the substrate surface to clean the substrate surface; reducing the rotation speed of the substrate to a low speed; moving an ultrasonic / megason device close to the substrate surface with a gap d between them; completely filling the gap d with the high-temperature chemical solution; turning on the ultrasonic / megason device and providing a constant or pulsed power supply during a first cleaning cycle; turning off the ultrasonic / megason device and spraying a high-temperature chemical solution or deionized water onto the substrate surface to release bubbles generated by the ultrasonic / megason device and prevent bubbles from accumulating on the substrate surface; turning on the ultrasonic / megason device and providing a constant or pulsed power supply during a second cleaning cycle; turning off the ultrasonic / megason device and spraying a chemical solution or deionized water onto the substrate surface; and drying the substrate; wherein the first and second cleaning cycles are repeated multiple times, with a bubble release step between each two cleaning cycles.

[0009] This invention also proposes a method for cleaning a substrate, comprising: rotating the substrate; spraying deionized water onto the substrate surface to pre-wet the substrate surface; spraying a high-temperature chemical solution onto the substrate surface to clean the substrate surface; reducing the rotation speed of the substrate to a low speed; moving an ultrasonic / megason device close to the substrate surface and having a gap d between the ultrasonic / megason device and the substrate surface, with the high-temperature chemical solution completely filling the gap d; turning on the ultrasonic / megason device and providing a constant or pulsed power supply during a first cleaning cycle; turning off the ultrasonic / megason device; raising the ultrasonic / megason device to remove it from the surface of the high-temperature chemical solution to release bubbles accumulated below and around the ultrasonic / megason device; moving the ultrasonic / megason device downward to create a gap d between the ultrasonic / megason device and the substrate surface; then turning on the ultrasonic / megason device and providing a constant or pulsed power supply during a second cleaning cycle; turning off the ultrasonic / megason device and spraying a chemical solution or deionized water onto the substrate surface; and drying the substrate; wherein the first and second cleaning cycles are repeated multiple times, with a bubble release step between each two cleaning cycles.

[0010] This invention also proposes a method for cleaning a substrate, comprising: rotating the substrate; spraying deionized water onto the substrate surface to pre-wet the substrate surface; spraying a high-temperature chemical solution or deionized water onto the substrate surface to clean the substrate surface; spraying a medium-temperature chemical solution or deionized water onto the substrate surface to clean the substrate surface; reducing the rotation speed of the substrate to a low speed, moving the ultrasonic / megason device to a position close to the substrate surface, and working in conjunction with the medium-temperature chemical solution to completely fill the gap d between the ultrasonic / megason device and the substrate surface; turning on the ultrasonic / megason device and providing a constant or pulsed power supply in a first cleaning cycle; spraying a medium-temperature chemical solution or deionized water onto the substrate surface to release bubbles generated by the medium-temperature chemical solution and prevent bubbles from accumulating on the substrate surface; turning on the ultrasonic / megason device and providing a constant or pulsed power supply in a second cleaning cycle; turning off the ultrasonic / megason device and spraying a chemical solution or deionized water onto the substrate surface; and drying the substrate; wherein the first and second cleaning cycles are repeated multiple times, with a bubble release step between every two cleaning cycles. Attached Figure Description

[0011] Figure 1A-1B The operation of a bellows pump according to an exemplary embodiment is described;

[0012] Figures 2A-2D An embodiment of a system having a buffer tank and two pumps is described;

[0013] Figure 3 An embodiment of a system with two buffer tanks and three pumps is described;

[0014] Figure 4Examples of high-temperature chemical mixing, heating, and conveying systems are described;

[0015] Figures 5A-5B An embodiment of a substrate cleaning apparatus having an ultrasonic / megasonite device is described. Detailed Implementation

[0016] This invention proposes a high-temperature chemical solution supply system for cleaning substrates. The system includes: a solution tank for containing a chemical solution; a first pump, the inlet of which is connected to the solution tank, and the outlet of which is connected to a buffer tank; a buffer tank including a tank body, an exhaust pipe, and a needle valve, one end of the exhaust pipe being connected to the tank body and the other end to the solution tank, and the needle valve being mounted on the exhaust pipe for regulating the pressure within the buffer tank; and a second pump, the inlet of which is connected to the buffer tank, and the outlet of which is connected to a cleaning chamber for cleaning the substrate. When the second pump is in the open state, the first pump and the needle valve are also in the open state. The pressure within the buffer tank is regulated by the needle valve and the first pump, causing the chemical solution in the buffer tank to be forced into the inlet of the second pump.

[0017] This invention also proposes an apparatus for cleaning a substrate. The apparatus includes a solution tank for containing a chemical solution; a first pump, the inlet of which is connected to the solution tank, and the outlet of which is connected to a buffer tank; a buffer tank including a tank body, an exhaust pipe, and a needle valve, one end of which is connected to the tank body and the other end to the solution tank, and the needle valve mounted on the exhaust pipe for adjusting the pressure within the buffer tank; and a second pump, the inlet of which is connected to the buffer tank, and the outlet of which is connected to a cleaning chamber for cleaning the substrate, wherein when the second pump is in the open state, the first pump and the needle valve are also in the open state, and the pressure within the buffer tank is adjusted by the needle valve and the first pump to force the chemical solution in the buffer tank into the inlet of the second pump; a substrate chuck for carrying the substrate; a rotary drive device connected to the substrate chuck and driving the substrate chuck to rotate; a nozzle for spraying a high-temperature chemical solution or deionized water onto the substrate surface; an ultrasonic / megason device positioned close to the substrate, with a gap between the substrate and the ultrasonic / megason device; and a vertical actuator for driving the ultrasonic / megason device to rise or fall to change the gap between the substrate and the ultrasonic / megason device.

[0018] Figure 1A-1B This diagram illustrates the working principle of a commonly used bellows pump. The bellows pump 1003 includes a left bellows chamber 1033 and a right bellows chamber 1035. For example... Figure 1A As shown, when air is expelled, the left bellows chamber 1033 draws in liquid. When the liquid is a high-temperature chemical, such as SC1 with a temperature above 70°C, bubbles 1037 (mainly oxygen and ammonia from the decomposition of hydrogen peroxide and ammonia) are generated during the liquid intake process. In the next pumping cycle, when air is supplied, the bubbles 1037 mixed with the chemical solution in the left bellows chamber 1033 will be expelled from the left bellows chamber 1033, as... Figure 1B As shown, bubble 1037 will be compressed to a smaller volume. Therefore, the liquid pressure at the outlet of pump 1003 will be significantly reduced. In addition, the chemical solution mixed with bubble 1037 will cause the pump, heater, flow meter and ultrasonic equipment to lose their function during the cleaning process.

[0019] Figures 2A-2D The diagram illustrates a specific embodiment of a pump system according to the present invention. For example... Figure 2A As shown, the system includes a first pump 2019, a buffer tank 2021, a second pump 2023, a needle valve 2029, and an exhaust pipe 2030. The chemical solution pumped from the first pump 2019 contains the aforementioned bubbles. These bubbles, mixed with the chemical solution, are pumped into the buffer tank 2021. In the buffer tank 2021, the bubbles rise to the top and are then discharged through the needle valve 2029 and the exhaust pipe 2030. The needle valve 2029 needs to be adjusted to sufficiently expel most of the bubbles without releasing too much pressure within the buffer tank 2021. By adjusting the output pressure of the first pump 2019, the pressure range within the buffer tank 2021 is between 5 psi and 20 psi, preferably 10 psi. Then, the chemical solution containing a small amount of bubbles in the buffer tank 2021 is forced into the inlet of the second pump 2023. Because the chemical solution being forced into the inlet of the second pump 2023 has a certain pressure (approximately set to 10 psi), fewer or fewer bubbles will be generated during the intake process of the second pump 2023. Therefore, the outlet pressure of the second pump 2023 can be maintained at a high value, and the outlet pressure of the second pump 2023 can be set up to 20-50 psi. Typically, the first pump 2019 can be either a centrifugal pump or a bellows pump. The second pump 2023 is preferably a bellows pump to achieve higher pressure output.

[0020] Figure 2B The diagram illustrates a specific embodiment of the buffer tank according to the present invention. The buffer tank includes a tank body 2022, an inlet pipe 2028, a needle valve 2029, an exhaust pipe 2030, and an outlet pipe 2032. The inlet pipe 2028 and the outlet pipe 2032 are inserted near the bottom of the tank body 2022. The exhaust pipe 2030 is installed at the top of the buffer tank 2021, allowing air bubbles 2037 in the chemical solution to rise and exit the buffer tank 2021 through the exhaust pipe 2030.

[0021] Figure 2C The diagram shows another specific embodiment of the buffer groove according to the present invention. This buffer groove is related to... Figure 2B Similar to the buffer tank 2021, the difference lies in that the buffer tank 2021 also includes a bubble separator 2034. The function of the bubble separator 2034 is to prevent bubbles 2037 output from the inlet pipe 2028 from entering the outlet pipe 2032. The height of the bubble separator 2034 is 50%-80% of the height of the buffer tank, preferably 70%.

[0022] Figure 2D The diagram shows another specific embodiment of the buffer groove according to the present invention. This buffer groove is related to... Figure 2B Similar to the previous model, the difference lies in that the buffer tank 2021 also includes a particulate filter 2036. The outlet pipe 2032 is installed at the top of the buffer tank 2021 and located at the outlet of the particulate filter 2036. The inlet pipe 2028 is inserted near the bottom of the tank body 2022 and located at the inlet of the particulate filter 2036. The vent pipe 2030 is installed at the top of the buffer tank 2021 and located at the inlet of the particulate filter 2036. The function of the particulate filter 2036 is to prevent air bubbles 2037 from directly entering the outlet pipe 2032 through the filter membrane; the air bubbles 2037 blocked by the filter membrane are discharged through the vent pipe 2030 and the needle valve 2029.

[0023] Figure 3 The diagram illustrates another specific embodiment of the pump system according to the present invention. This system is related to... Figure 2A Similar to the one shown, the difference lies in that the system also includes a second buffer tank 3035 and a fourth pump 3053. This three-pump system, compared to a two-pump system, enables chemicals to achieve higher pressures and greater flow rates at higher temperatures. Clearly, more pumps and buffer tanks can be combined to achieve even greater pressures and flow rates.

[0024] Figure 4 The diagram illustrates a specific embodiment of a hot chemical solution supply system according to the present invention. The system includes a solution tank 4001, a first pump 4019, a buffer tank 4021, a second pump 4023, a third pump 4003, a heater 4013, a thermometer 4005, and a controller 4008. The solution tank 4001 is provided with a first inlet 4017 for water intake, a second inlet 4015 for a first chemical solution such as hydrogen peroxide, and a third inlet 4009 for a second chemical solution such as ammonia. The solution tank 4001 further includes a drain pipe 4007 for discharging the chemical solution from the solution tank 4001. The outer surface of the solution tank 4001 is covered with a heat-insulating material such as rubber or foam for insulation, and all liquid pipes connecting the solution tank 4001, the first pump 4019, the buffer tank 4021, the second pump 4023, the third pump 4003, and the heater 4013 are covered with the same heat-insulating material. The operating steps of the high-temperature chemical solution supply system are as follows:

[0025] Step 1: Pour the required amount of water (deionized water) into solution tank 4001. In order to shorten the heating time, if the temperature of the final mixed chemical solution needs to reach above 60°C, hot water with a temperature of 60°C can be poured in.

[0026] Step 2: Inject the first chemical solution of the required concentration, such as hydrogen peroxide;

[0027] Step 3: Inject a second chemical solution of the required concentration, such as ammonia;

[0028] Step 4: Turn on the third pump 4003, and set the air pressure to 20-60 psi, preferably 40 psi;

[0029] Step 5: Turn on heater 4013 and set the temperature to T0. The temperature can be set between 35℃ and 95℃.

[0030] Step 6: When the thermometer 4005 shows that the temperature of the chemical solution in the solution tank 4001 has reached the set temperature T0, turn on the first pump 4019 and set the output pressure P1 between 5-30 psi, preferably 15 psi.

[0031] Step 7: Adjust needle valve 4029 to achieve a flow rate that is just enough to expel air bubbles. In order to save chemical solution, the air bubbles that are expelled and mixed with the chemical solution such as SC1 will return to solution tank 4001 through exhaust pipe 4030.

[0032] Step 8: Turn on the second pump 4023 and set the output pressure P2 between 10-80 psi, with P2 greater than P1;

[0033] Step 9: Since the second pump 4023 is turned on, the change in pressure P1 may affect the flow rate of the exhaust pipe 4030. Therefore, readjust the needle valve 4029 to achieve a flow rate that is just enough to expel the air bubbles.

[0034] Figures 5A-5B The diagram illustrates a specific embodiment of a substrate cleaning apparatus equipped with an ultrasonic / megasonite device. This substrate cleaning apparatus includes a substrate 5010, a substrate chuck 5014 driven to rotate by a rotary drive device 5016, a nozzle 5012 for spraying a chemical solution or deionized water 5032, and an ultrasonic / megasonite (ultrasonic waves operating at a frequency of MHz) device 5003. The ultrasonic / megasonite device 5003 also includes a piezoelectric sensor 5004 and a paired acoustic resonator 5008. When the sensor 5004 is energized, it vibrates, and the resonator 5008 transfers high-frequency acoustic energy to the chemical solution or deionized water 5032. The vibration generated by the megasonite energy loosens particles on the substrate 5010, which are then removed from the surface of the substrate 5010 by the flowing chemical solution or deionized water 5032 provided by the nozzle 5012.

[0035] The substrate cleaning apparatus also includes a support beam 5007, a guide screw 5005, and a vertical actuator 5006. The gap d between the ultrasonic / megasonic device 5003 and the substrate 5010 increases or decreases during the cleaning process as the substrate chuck 5014 rotates. The control unit 5088 controls the speed of the vertical actuator 5006 based on the speed of the rotary drive 5016.

[0036] In one specific embodiment, air bubbles accumulating below or around the ultrasonic / megason device 5003 are released by controlling the gap d. The gap d between the ultrasonic / megason device 5003 and the surface of the substrate 5010 is high enough that the working surface of the ultrasonic / megason device 5003 is not immersed in the cleaning chemical solution 5032.

[0037] As ultrasonic / megason waves are input into the gap between the substrate 5010 and the ultrasonic / megason device 5003, high-temperature chemical solutions, such as SC1, exceeding 70°C, will generate bubbles. This will increase the reflected power of the ultrasonic / megason device, causing the ultrasonic / megason power supply to shut down. Simultaneously, the small amount of ultrasonic / megason power in the gap will reduce the cleaning effect on the substrate 5010. Furthermore, bubbles on the surface of the substrate 5010 may prevent the chemical solution and ultrasonic / megason waves from contacting the substrate 5010, resulting in uncleaned areas and defects on the substrate 5010.

[0038] To reduce air bubbles generated during ultrasonic / megason assisted cleaning, the cleaning process is divided into several stages to minimize bubbles. The specific method provided by this invention includes the following steps:

[0039] Step 1: The substrate chuck 5014 drives the substrate 5010 to rotate, with the rotation speed set to 300-1200 rpm, preferably 500 rpm;

[0040] Step 2: Use nozzle 5012 to spray deionized water onto the surface of substrate 5010 to pre-wet the surface of substrate 5010;

[0041] Step 3: Use nozzle 5012 to spray a high-temperature (greater than 70°C) chemical solution, such as SC1, onto the surface of substrate 5010 to clean the surface of substrate 5010;

[0042] Step 4: Reduce the rotation speed of the substrate to a low speed (10-200 rpm), and move the ultrasonic / megason device to a position close to the surface of the substrate 5010, with a gap d between the substrate 5010 and the surface of the substrate 5010. The chemical solution completely fills the gap d between the surface of the substrate 5010 and the ultrasonic / megason device 5003, so that the working surface of the ultrasonic / megason device 5003 is immersed in the chemical solution;

[0043] Step 5: Turn on the ultrasonic / megasonite device 5003 and provide a constant or pulsed power supply during the first cleaning cycle. In this step, the gap d is controlled by the vertical driver 5006.

[0044] The waveform of the ultrasonic / megasonite power supply is programmable and preset according to the formula, and the trajectory of the gap d variation is also programmable and preset according to the formula.

[0045] Step 6: Turn off the ultrasonic / megason device. Spray a high-temperature chemical solution or deionized water onto the substrate 5010 surface to release the bubbles generated by the ultrasonic / megason device in step 5, to prevent bubbles from accumulating on the substrate surface;

[0046] In this bubble release step, the type of chemical solution sprayed can be the same as or different from the type of cleaning chemical solution.

[0047] The sprayed chemical solution completely fills the gap d between the substrate surface and the ultrasonic / megason device, so that the working surface of the ultrasonic / megason device is immersed in the chemical solution.

[0048] The substrate rotation speed can be set higher to better release bubbles.

[0049] The gap d can be set larger to better release air bubbles.

[0050] The power supply to the ultrasonic / megason device can be set to a lower level or completely shut off for better bubble release.

[0051] For production considerations, the time for this bubble release step can be set to a few seconds.

[0052] Step 7: Turn on the ultrasonic / megasonite device 5003 and provide a constant or pulsed power supply during the second cleaning cycle, in which the gap d is controlled by the vertical driver 5006;

[0053] The waveform of the ultrasonic / megasonite power supply is programmable and preset according to the formula, and the trajectory of the gap d variation is also programmable and preset according to the formula.

[0054] Steps 6 and 7 can be repeated continuously to enhance the cleaning effect.

[0055] The first and second cleaning cycles are repeated multiple times, with a bubble release step between each two cleaning cycles. The first and second cleaning cycles can be the same or different.

[0056] Step 8: Turn off the ultrasonic / megason device 5003, and use nozzle 5012 to spray chemical solution or deionized water onto substrate 5010;

[0057] Step 9: Dry substrate 5010.

[0058] Another method for preventing the generation of air bubbles during ultrasonic / megason assisted cleaning provided by the present invention includes the following steps:

[0059] Step 1: The substrate chuck 5014 drives the substrate 5010 to rotate. The rotation speed is set to 300-1200 rpm, preferably 500 rpm.

[0060] Step 2: Use nozzle 5012 to spray deionized water onto the surface of substrate 5010 to pre-wet the surface of substrate 5010.

[0061] Step 3: Use nozzle 5012 to spray a high-temperature (greater than 70°C) chemical solution, such as SC1, onto the surface of substrate 5010 to clean the surface of substrate 5010;

[0062] Step 4: Reduce the rotation speed of the substrate to a low speed (10-200 rpm), move the ultrasonic / megason device 5003 to a position close to the surface of the substrate 5010 and with a gap d between the substrate 5010 and the surface of the substrate 5010, and completely fill the gap between the surface of the substrate 5010 and the ultrasonic / megason device 5003 with the chemical solution, so that the working surface of the ultrasonic / megason device 5003 is immersed in the chemical solution.

[0063] Step 5: Turn on the ultrasonic / megasonite device 5003 and provide a constant or pulsed power supply during the first cleaning cycle. In this step, the gap d is controlled by the vertical driver 5006.

[0064] The waveform of the ultrasonic / megasonite power supply is programmable and preset according to the formula, and the trajectory of the gap d variation is also programmable and preset according to the formula.

[0065] Step 6: Turn off the ultrasonic / megason device, then raise the ultrasonic / megason device to remove it from the surface of the high-temperature chemical solution to release any bubbles that have accumulated below or around the ultrasonic / megason device.

[0066] In this bubble release step, the sprayed chemical solution may be the same as or different from the cleaning chemical solution.

[0067] The ultrasonic / megason device is raised, and the gap d between the ultrasonic / megason device and the substrate surface is high enough that the working surface of the ultrasonic / megason device is not immersed in the cleaning chemical solution.

[0068] The substrate rotation speed can be set higher to better release bubbles.

[0069] The power supply to the ultrasonic / megason device can be set to a lower level or completely shut off for better bubble release.

[0070] For production considerations, the time for this bubble release step can be set to a few seconds.

[0071] Step 7: Move the ultrasonic / megason device 5003 downward to create a gap d between the ultrasonic / megason device and the substrate 5010, then turn on the ultrasonic / megason device 5003 and provide a constant or pulsed operating power supply in the second cleaning cycle. In this step, the gap d is controlled by the vertical driver 5006.

[0072] The waveform of the ultrasonic / megasonite power supply is programmable and preset according to the formula, and the trajectory of the gap d variation is also programmable and preset according to the formula.

[0073] Steps 6 and 7 can be repeated continuously to enhance the cleaning effect.

[0074] The first and second cleaning cycles are repeated multiple times, with a bubble release step between every two cleaning cycles. The first and second cleaning cycles can be the same or different.

[0075] Step 8: Turn off the ultrasonic / megason device 5003 and spray chemical solution or deionized water onto the substrate 5010.

[0076] Step 9: Dry substrate 5010.

[0077] Another method for preventing the generation of air bubbles during ultrasonic / megason assisted cleaning provided by the present invention includes the following steps:

[0078] Step 1: The substrate chuck 5014 drives the substrate 5010 to rotate. The rotation speed is set to 300-1200 rpm, preferably 500 rpm.

[0079] Step 2: Use nozzle 5012 to spray deionized water onto the surface of substrate 5010 to pre-wet the surface of substrate 5010.

[0080] Step 3: Spray a high-temperature chemical solution or deionized water onto the surface of substrate 5010 using a scanning nozzle. The scanning path is programmable and can be set according to the formula.

[0081] Step 4: Spray a medium-temperature chemical solution (25℃-70℃) or deionized water onto the surface of substrate 5010 to clean the surface of substrate 5010.

[0082] The types of medium-temperature chemical solutions and high-temperature chemical solutions can be the same or different.

[0083] Step 5: Reduce the rotation speed of the substrate to a low speed (10-500 rpm), move the ultrasonic / megason device 5003 to a position close to the surface of the substrate 5010, and work together with the medium-temperature chemical solution to completely fill the gap d between the ultrasonic / megason device and the substrate surface. In this way, the working surface of the ultrasonic / megason device is immersed in the chemical solution.

[0084] Step 6: Turn on the ultrasonic / megason device and provide a constant or pulsed power supply during the first cleaning cycle. In this step, the gap d is controlled by the vertical driver.

[0085] The waveform of the ultrasonic / megasonite power supply is programmable and preset according to the formula, and the trajectory of the gap d variation is also programmable and preset according to the formula.

[0086] Step 7: Spray a medium-temperature chemical solution or deionized water onto the substrate surface to release the bubbles generated by the medium-temperature chemical solution, thereby preventing the bubbles from accumulating on the substrate surface.

[0087] In this bubble release step, the type of chemical solution sprayed can be the same as or different from the type of cleaning chemical solution.

[0088] The substrate rotation speed can be set higher to better release bubbles.

[0089] The gap d can be set larger to better release air bubbles.

[0090] The power supply to the ultrasonic / megason device can be set to a lower level or completely shut off for better bubble release.

[0091] For production considerations, the time for this bubble release step can be set to a few seconds.

[0092] Step 8: Turn on the ultrasonic / megason device and provide constant or pulsed power during the second cleaning cycle. In this step, the gap d is controlled by the vertical driver.

[0093] The waveform of the ultrasonic / megasonite power supply is programmable and preset according to the formula, and the trajectory of the gap d variation is also programmable and preset according to the formula.

[0094] Steps 7 and 8 can be repeated continuously to enhance the cleaning effect.

[0095] The first and second cleaning cycles are repeated multiple times, with a bubble release step between every two cleaning cycles. The first and second cleaning cycles can be the same or different.

[0096] Step 9: Turn off the ultrasonic / megason device and spray chemical solution or deionized water onto the substrate.

[0097] Step 10: Dry the substrate.

Claims

1. A chemical solution supply system for cleaning a substrate, comprising: Solution tank, used to hold chemical solutions; The first pump has its inlet connected to a solution tank and its outlet connected to a buffer tank. The buffer tank includes a tank body, an exhaust pipe, and a needle valve. One end of the exhaust pipe is connected to the tank body, and the other end is connected to the solution tank. The needle valve is installed on the exhaust pipe and is used to regulate the pressure inside the buffer tank. as well as The second pump has its inlet connected to a buffer tank and its outlet connected to a cleaning chamber for cleaning the substrate. (i) When the second pump is in the open state, the first pump and the needle valve are also in the open state, and the pressure of the first pump and the opening degree of the needle valve are adjusted so that the pressure in the buffer tank is 5psi~20psi, and the chemical solution in the buffer tank is forced into the inlet of the second pump, and the air bubbles in the chemical solution pumped into the tank by the first pump are discharged. (ii) During the process of the second pump supplying the chemical solution to the cleaning chamber, the chemical solution continuously flows from the solution tank through the first pump, the buffer tank and the second pump to the cleaning chamber, and air bubbles continuously exit from the needle valve into the buffer tank.

2. The liquid supply system according to claim 1, characterized in that, It further includes a third pump and a heater, the third pump being connected to the solution tank and the heater being connected to the solution tank.

3. The liquid supply system according to claim 1, characterized in that, Further components include a thermometer and a controller.

4. The liquid supply system according to claim 1, characterized in that, The solution tank has a first inlet for introducing deionized water, a second inlet for introducing a first chemical solution, and a third inlet for introducing a second chemical solution.

5. The liquid supply system according to claim 4, characterized in that, The first chemical solution is hydrogen peroxide, and the second chemical solution is ammonia.

6. The liquid supply system according to claim 1, characterized in that, The buffer tank also includes an inlet pipe and an outlet pipe, which are inserted near the bottom of the tank. An exhaust pipe is installed at the top of the buffer tank, and bubbles in the chemical solution rise and are discharged from the buffer tank through the exhaust pipe.

7. The liquid supply system according to claim 6, characterized in that, The buffer tank also includes a bubble separator to prevent bubbles from the inlet pipe from entering the outlet pipe.

8. The liquid supply system according to claim 1, characterized in that, The buffer tank also includes an inlet pipe, an outlet pipe, and a particulate filter. The inlet pipe is inserted near the bottom of the tank and is located at the inlet of the particulate filter. The outlet pipe is installed at the top of the buffer tank and is located at the outlet of the particulate filter. The exhaust pipe is installed at the top of the buffer tank and is located at the inlet of the particulate filter.

9. The liquid supply system according to claim 1, characterized in that, It further includes at least one second buffer tank and at least one fourth pump disposed between the outlet of the second pump and the cleaning chamber.

10. The liquid supply system according to claim 1, characterized in that, The outer surface of the solution tank is covered with heat-insulating material.

11. A substrate cleaning apparatus, comprising: Solution tank, used to hold chemical solutions; The first pump has its inlet connected to a solution tank and its outlet connected to a buffer tank. The buffer tank includes a tank body, an exhaust pipe, and a needle valve. One end of the exhaust pipe is connected to the tank body, and the other end is connected to the solution tank. The needle valve is installed on the exhaust pipe and is used to regulate the pressure inside the buffer tank. as well as The second pump has its inlet connected to a buffer tank and its outlet connected to a cleaning chamber for cleaning the substrate. (i) When the second pump is in the open state, the first pump and the needle valve are also in the open state. The pressure of the first pump and the opening degree of the needle valve are adjusted to make the pressure in the buffer tank 5psi~20psi, so that the chemical solution in the buffer tank is forced into the inlet of the second pump and the air bubbles in the chemical solution pumped into the tank by the first pump are discharged. (ii) During the process of the second pump supplying chemical solution to the cleaning chamber, the chemical solution continuously flows from the solution tank through the first pump, the buffer tank and the second pump to the cleaning chamber, and air bubbles are continuously discharged from the needle valve into the buffer tank. Substrate chuck, which supports the substrate; A rotary drive unit connects to the substrate chuck and drives the substrate chuck to rotate; The nozzle sprays a chemical solution or deionized water onto the substrate surface. An ultrasonic / megason device is positioned close to a substrate, with a gap between the substrate and the ultrasonic / megason device. A vertical actuator drives the ultrasonic / megason device to rise or fall to change the gap between the substrate and the ultrasonic / megason device.

12. A substrate cleaning method, wherein the substrate cleaning method is performed using the substrate cleaning apparatus as described in claim 11, the substrate cleaning method comprising: Rotating substrate; Spray deionized water onto the substrate surface to pre-wet the substrate surface; A chemical solution is sprayed onto the substrate surface to clean it. Reduce the rotation speed of the substrate to a low speed, move the ultrasonic / megason device to a position close to the substrate surface and with a gap d between them, and completely fill the gap d with chemical solution. Turn on the ultrasonic / megasonite device and provide a constant or pulsed power supply during the first cleaning cycle; Turn off the ultrasonic / megason device and spray a chemical solution or deionized water onto the substrate surface to release the bubbles generated by the ultrasonic / megason device and prevent the bubbles from accumulating on the substrate surface. Turn on the ultrasonic / megasonite device and provide constant or pulsed power during the second cleaning cycle; Turn off the ultrasonic / megason device and spray chemical solution or deionized water onto the substrate surface; Dry substrate; The first and second cleaning cycles are repeated multiple times, with a bubble release step between each two cleaning cycles.

13. The method according to claim 12, characterized in that, The chemical solution is SC1 at high temperature.

14. The method according to claim 12, characterized in that, In the step of turning on the ultrasonic / megason device and providing a constant or pulsed power supply during the first cleaning cycle, the gap d is controlled by a vertical driver, the waveform of the ultrasonic / megason power supply is programmable and preset, and the trajectory of the gap d variation is also programmable and preset.

15. The method according to claim 12, characterized in that, In the bubble release step, the type of chemical solution sprayed can be the same as or different from the type of cleaning chemical solution.

16. The method according to claim 12, characterized in that, The first and second cleaning cycles are the same.

17. The method according to claim 12, characterized in that, The first cleaning cycle is different from the second cleaning cycle.

18. A substrate cleaning method, wherein the substrate cleaning method is performed using the substrate cleaning apparatus of claim 11, the substrate cleaning method comprising: Rotating substrate; Spray deionized water onto the substrate surface to pre-wet the substrate surface; A chemical solution is sprayed onto the substrate surface to clean it. Reduce the rotation speed of the substrate to a low speed, move the ultrasonic / megason device to a position close to the substrate surface and with a gap d between them, and completely fill the gap d with chemical solution. Turn on the ultrasonic / megasonite device and provide a constant or pulsed power supply during the first cleaning cycle; Turn off the ultrasonic / megason device, raise the ultrasonic / megason device to remove it from the surface of the chemical solution to release the bubbles that have accumulated below and around the ultrasonic / megason device. Move the ultrasonic / megason device downward to create a gap d between the ultrasonic / megason device and the substrate surface, then turn on the ultrasonic / megason device and provide a constant or pulsed power supply during the second cleaning cycle. Turn off the ultrasonic / megason device and spray chemical solution or deionized water onto the substrate surface; Dry substrate; The first and second cleaning cycles are repeated multiple times, with a bubble release step between each two cleaning cycles.

19. The method according to claim 18, characterized in that, Raise the ultrasonic / megason device and control the gap d between the ultrasonic / megason device and the substrate surface to prevent the working surface of the ultrasonic / megason device from being immersed in the chemical solution.

20. The method according to claim 18, characterized in that, The first and second cleaning cycles are the same.

21. The method according to claim 18, characterized in that, The first cleaning cycle is different from the second cleaning cycle.

22. A substrate cleaning method, wherein the substrate cleaning method is performed using the substrate cleaning apparatus of claim 11, the substrate cleaning method comprising: Rotating substrate; Spray deionized water onto the substrate surface to pre-wet the substrate surface; Spray a chemical solution or deionized water onto the substrate surface to clean it; Spray a medium-temperature chemical solution or deionized water onto the substrate surface to clean it; Reduce the rotation speed of the substrate to a low speed, move the ultrasonic / megason device to a position close to the substrate surface, and work together with the medium-temperature chemical solution to completely fill the gap d between the ultrasonic / megason device and the substrate surface. Turn on the ultrasonic / megasonite device and provide a constant or pulsed power supply during the first cleaning cycle; Spray a medium-temperature chemical solution or deionized water onto the substrate surface to release the bubbles generated by the medium-temperature chemical solution and prevent the bubbles from accumulating on the substrate surface; Turn on the ultrasonic / megasonite device and provide constant or pulsed power during the second cleaning cycle; Turn off the ultrasonic / megason device and spray chemical solution or deionized water onto the substrate surface; Dry substrate; The first and second cleaning cycles are repeated multiple times, with a bubble release step between each two cleaning cycles.

23. The method according to claim 22, characterized in that, The types of intermediate-temperature chemical solutions are the same as or different from the types of chemical solutions.

24. The method according to claim 22, characterized in that, In the bubble release step, the type of chemical solution sprayed can be the same as or different from the cleaning chemical solution.

25. The method according to claim 22, characterized in that, The first and second cleaning cycles are the same.

26. The method according to claim 22, characterized in that, The first cleaning cycle is different from the second cleaning cycle.

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