A remote plasma chamber cleaning method using 3,3,4,4,4-pentafluoro-1-butene and a control method thereof

Abstract

The present application relates to a remote plasma chamber cleaning method using 3,3,4,4,4-pentafluoro-1-butene and a control method thereof, including a remote plasma source, a gas supply unit, a vacuum chamber, a vacuum exhaust unit and a bypass gas path. 3,3,4,4,4-pentafluoro-1-butene is used as the main cleaning gas, and the delayed introduction of oxygen-containing gas can efficiently remove SiO2, SiN x and other silicon-based dielectric deposits; the bypass gas path separates the oxygen-containing gas from the remote discharge area, avoiding polymerization / redeposition and side reactions, and improving cleaning repeatability; through pipeline temperature control, pressure regulation and inert gas assistance, the design is suitable for different cavity volumes and film layer states, reducing the risk of equipment corrosion; dynamic parameter adjustment and multi-method endpoint detection avoid over-cleaning, reduce material loss and chamber damage; based on the cavity and film layer information, the parameters are initialized, and the process is dynamically optimized based on real-time pressure, gas composition and other data to automatically complete the cleaning, termination and reset processes.

Description

Technical Field

[0001] This invention relates to the field of semiconductor manufacturing equipment maintenance and cleaning, specifically to a remote plasma chamber cleaning method and control method using 3,3,4,4,4-pentafluoro-1-butene. Background Technology

[0002] In semiconductor manufacturing, vacuum chambers, as core process equipment, have long been used in critical steps such as thin film deposition and etching. During this process, SiO2 and SiN... x Silicon-based dielectric materials will inevitably be deposited on the surfaces of critical components such as the inner walls of the chamber, electrodes, and gas pipelines.

[0003] Existing chamber cleaning technologies mainly rely on plasma cleaning schemes containing fluorine gases. In traditional cleaning processes, oxygen-containing gases are often mixed with fluorine-containing gases and then introduced into the plasma discharge zone. During this process, excessive reactions can easily occur to generate complex polymers. These polymers can deposit inside the chamber or in the pipeline, causing secondary pollution, reducing cleaning repeatability, and may even block gas channels, affecting the normal operation of the equipment.

[0004] In different semiconductor manufacturing scenarios, the volume of the vacuum chamber, the type and thickness of the film to be cleaned vary. Traditional cleaning processes often use fixed parameter modes, which are difficult to adapt to diverse cleaning needs. This can easily lead to problems such as incomplete cleaning or over-cleaning. Incomplete cleaning will result in deposit residue, while over-cleaning will aggravate corrosion and wear of chamber components, shorten equipment lifespan, and increase material costs.

[0005] Therefore, there is a need for a remote plasma chamber cleaning method and its control method using 3,3,4,4,4-pentafluoro-1-butene, which can solve the above problems. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art, adapt to practical needs, and provide a remote plasma chamber cleaning method and control method using 3,3,4,4,4-pentafluoro-1-butene. This method can avoid polymer deposition inside the chamber and can be adapted to different chamber volumes and film states, thereby reducing the risk of equipment corrosion.

[0007] To achieve the objectives of this invention, the technical solution adopted is as follows: A remote plasma chamber cleaning method and its control method using 3,3,4,4,4-pentafluoro-1-butene are designed, comprising a remote plasma source, a gas supply unit, a vacuum chamber, a vacuum pumping unit, and a bypass gas path. The method includes the following steps:

[0008] S1. Control the vacuum pumping unit to pre-evacuate the chamber, so that the pressure inside the chamber drops to a preset initial vacuum level;

[0009] S2. Cleaning gas is supplied to a remote plasma source through the gas supply unit. The cleaning gas has 3,3,4,4,4-pentafluoro-1-butene as its main component, and the volume percentage of 3,3,4,4,4-pentafluoro-1-butene in the cleaning gas is not less than 80%. The temperature of the pipeline used to supply the cleaning gas and oxygen-containing gas is maintained at 30-80°C to suppress condensation.

[0010] S3. Start the remote plasma source to ionize the cleaning gas to generate fluorine-containing active free radicals. Control the fluorine-containing active free radicals to enter the pre-evacuated vacuum chamber through the gas transmission channel, and contact the silicon-based dielectric deposit on the inner wall of the chamber to undergo a chemical reaction.

[0011] S4. The remote plasma source is continuously maintained, and oxygen-containing gas is introduced into the vacuum chamber through the bypass gas path, so that the oxygen-containing gas interacts with fluorine-containing active free radicals in the chamber. The bypass gas path bypasses the discharge region of the remote plasma source, and the oxygen-containing gas is introduced after a delay of t seconds after the start of step S3, where t is 1 to 30 seconds. At the same time, the gaseous products generated by the reaction are discharged from the vacuum chamber through the vacuum pumping unit to maintain the preset cleaning time.

[0012] S5. After cleaning, shut down the remote plasma source and gas supply unit, perform deep evacuation of the vacuum chamber through the vacuum pumping unit, and then introduce inert gas into the chamber to depressurize to atmospheric pressure, thus completing the chamber cleaning.

[0013] Preferably, the preset initial vacuum level in step S1 is 0.1 mbar to 10 mbar; and the preset cleaning time in step S4 is 5 min to 60 min.

[0014] Preferably, the cleaning gas further includes an inert diluent gas, which is at least one of argon and nitrogen, and the volume percentage of the inert diluent gas in the cleaning gas is 5% to 20%; the oxygen-containing gas is selected from one or more of O2, N2O, and CO2.

[0015] Preferably, in step S3, the remote plasma source is a radio frequency plasma source or a microwave plasma source with a working power of 200W to 6000W; during step S3, the vacuum chamber pressure is 0.3mbar to 12mbar.

[0016] Preferably, in step S4, the pressure in the vacuum chamber is maintained at 0.5 mbar to 15 mbar during the reaction process, and the chamber pressure is stabilized by adjusting the pumping speed of the vacuum pumping unit.

[0017] Preferably, the control method includes the following steps:

[0018] T1: Parameter initialization: Obtain the cavity information and membrane information of the vacuum chamber to be cleaned. The cavity information includes the cavity volume, and the membrane information includes the membrane type and membrane thickness data. Generate initial control parameters based on the cavity information and membrane information. The initial control parameters include the pre-vacuum target pressure, cleaning gas flow rate, remote plasma source power, and preset cleaning time.

[0019] T2: Process monitoring: The detection unit collects pressure data inside the vacuum chamber, working status data of the remote plasma source, and gas composition data of the exhaust port in real time, and transmits the collected data to the control device in real time.

[0020] T3: Parameter dynamic adjustment: The pressure data collected in real time is compared with the preset pressure threshold. If the pressure deviation exceeds the allowable range, the pumping speed of the vacuum pumping unit or the cleaning gas flow rate of the gas supply unit is adjusted. At the same time, the reaction process is judged based on the gas composition data of the exhaust port. If the reaction rate is lower than the preset threshold, the working power of the remote plasma source is adjusted.

[0021] T4: Cleaning Termination Judgment: The endpoint signal output by the endpoint detection module determines whether the cleaning meets the standard. The endpoint detection module is selected from one or more of optical emission spectroscopy (OES), exhaust Fourier transform infrared spectroscopy (FTIR), pressure change detection, or mass spectrometry. When the cleaning endpoint is reached, the cleaning is determined to meet the standard, and the cleaning termination and chamber reset process of step S5 of claim 1 is automatically executed. The cleaning gas supply is also terminated to reduce over-cleaning. If the standard is not met, the cleaning time is extended and continuous monitoring is carried out until the termination condition is met.

[0022] Preferably, the detection unit includes a multi-point pressure sensor, a plasma power detector, a gas chromatograph, and the endpoint detection module. The multi-point pressure sensor is used to collect pressure data in different areas of the vacuum chamber, and the gas chromatograph is used to detect the concentration of reaction products and the concentration of unreacted 3,3,4,4,4-pentafluoro-1-butene at the exhaust port. The gas supply unit includes a 3,3,4,4,4-pentafluoro-1-butene supply unit, a carrier gas supply unit, and an oxygen-containing gas supply unit. The 3,3,4,4,4-pentafluoro-1-butene supply unit includes a vaporizer for vaporizing liquid 3,3,4,4,4-pentafluoro-1-butene before supplying it. The first gas path and the bypass gas path of the cleaning system both include a mass flow controller, and the bypass gas path also includes a valve. The gas transmission channel includes a heating unit for maintaining the pipeline temperature at 30–80°C.

[0023] Preferably, the specific process of generating the initial control parameters in step T1 is as follows: calculate the required total amount of fluorine-containing active free radicals based on the film thickness data, and determine the cleaning gas flow rate and remote plasma source power in combination with the ionization efficiency of 3,3,4,4,4-pentafluoro-1-butene; determine the initial values ​​of the pre-vacuum target pressure and the preset cleaning time based on the cavity volume and film type; the control device is configured to open the valve of the bypass gas path 1 to 30 seconds after the activation gas is introduced into the vacuum chamber, so as to achieve the delayed introduction of oxygen-containing gas.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] 1. Using 3,3,4,4,4-pentafluoro-1-butene as the main cleaning gas, combined with delayed-introduction oxygen-containing gas, SiO2 and SiN can be efficiently removed. x Silicon-based dielectric deposits are obtained by separating oxygen-containing gas from the remote discharge region through a bypass gas path, avoiding polymerization or redeposition and side reactions, and improving cleaning repeatability.

[0026] 2. Through pipeline temperature control, pressure regulation and inert gas assistance, it adapts to different cavity volumes and film conditions, reducing the risk of equipment corrosion; dynamic parameter adjustment and multi-method endpoint detection avoid over-cleaning and reduce material loss and cavity damage.

[0027] 3. Based on the initialization parameters of the cavity and membrane layer information, and combined with real-time pressure, gas composition and other data, the process is dynamically optimized to automatically complete the cleaning, termination and reset process, simplifying the operation while ensuring cleaning stability. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the cleaning process of the present invention;

[0029] Figure 2 This is a schematic diagram of the control flow of the present invention; Detailed Implementation

[0030] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0031] A remote plasma chamber cleaning method and its control method using 3,3,4,4,4-pentafluoro-1-butene, comprising a remote plasma source, a gas supply unit, a vacuum chamber, a vacuum pumping unit, and a bypass gas path, the method comprising the following steps:

[0032] S1. Control the vacuum pumping unit to pre-evacuate the chamber, so that the pressure inside the chamber drops to a preset initial vacuum level;

[0033] S2. Cleaning gas is supplied to a remote plasma source through the gas supply unit. The cleaning gas has 3,3,4,4,4-pentafluoro-1-butene as its main component, and the volume percentage of 3,3,4,4,4-pentafluoro-1-butene in the cleaning gas is not less than 80%. The temperature of the pipeline used to supply the cleaning gas and oxygen-containing gas is maintained at 30-80°C to suppress condensation.

[0034] S3. Start the remote plasma source to ionize the cleaning gas to generate fluorine-containing active free radicals. Control the fluorine-containing active free radicals to enter the pre-evacuated vacuum chamber through the gas transmission channel, and contact the silicon-based dielectric deposit on the inner wall of the chamber to undergo a chemical reaction.

[0035] S4. The remote plasma source is continuously maintained, and oxygen-containing gas is introduced into the vacuum chamber through the bypass gas path, so that the oxygen-containing gas interacts with fluorine-containing active free radicals in the chamber. The bypass gas path bypasses the discharge region of the remote plasma source, and the oxygen-containing gas is introduced after a delay of t seconds after the start of step S3, where t is 1 to 30 seconds. At the same time, the gaseous products generated by the reaction are discharged from the vacuum chamber through the vacuum pumping unit to maintain the preset cleaning time.

[0036] S5. After cleaning, shut down the remote plasma source and gas supply unit, perform deep evacuation of the vacuum chamber through the vacuum pumping unit, and then introduce inert gas into the chamber to depressurize to atmospheric pressure, thus completing the chamber cleaning.

[0037] Specifically, the preset initial vacuum level in step S1 is 0.1 mbar to 10 mbar; the preset cleaning time in step S4 is 5 min to 60 min.

[0038] Furthermore, the cleaning gas also includes an inert diluent gas, which is at least one of argon and nitrogen, and the volume percentage of the inert diluent gas in the cleaning gas is 5% to 20%; the oxygen-containing gas is selected from one or more of O2, N2O, and CO2.

[0039] It is worth noting that in step S3, the remote plasma source is a radio frequency plasma source or a microwave plasma source with a working power of 200W to 6000W; during step S3, the vacuum chamber pressure is 0.3mbar to 12mbar.

[0040] It is worth noting that during the reaction in step S4, the pressure in the vacuum chamber is maintained between 0.5 mbar and 15 mbar, and the chamber pressure is stabilized by adjusting the pumping speed of the vacuum pumping unit.

[0041] It is worth mentioning that the control method includes the following steps:

[0042] T1: Parameter initialization: Obtain the cavity information and membrane information of the vacuum chamber to be cleaned. The cavity information includes the cavity volume, and the membrane information includes the membrane type and membrane thickness data. Generate initial control parameters based on the cavity information and membrane information. The initial control parameters include the pre-vacuum target pressure, cleaning gas flow rate, remote plasma source power, and preset cleaning time.

[0043] T2: Process monitoring: The detection unit collects pressure data inside the vacuum chamber, working status data of the remote plasma source, and gas composition data of the exhaust port in real time, and transmits the collected data to the control device in real time.

[0044] T3: Parameter dynamic adjustment: The pressure data collected in real time is compared with the preset pressure threshold. If the pressure deviation exceeds the allowable range, the pumping speed of the vacuum pumping unit or the cleaning gas flow rate of the gas supply unit is adjusted. At the same time, the reaction process is judged based on the gas composition data of the exhaust port. If the reaction rate is lower than the preset threshold, the working power of the remote plasma source is adjusted.

[0045] T4: Cleaning Termination Judgment: The endpoint signal output by the endpoint detection module determines whether the cleaning meets the standard. The endpoint detection module is selected from one or more of optical emission spectroscopy (OES), exhaust Fourier transform infrared spectroscopy (FTIR), pressure change detection, or mass spectrometry. When the cleaning endpoint is reached, the cleaning is determined to meet the standard, and the cleaning termination and chamber reset process of step S5 of claim 1 is automatically executed. The cleaning gas supply is also terminated to reduce over-cleaning. If the standard is not met, the cleaning time is extended and continuous monitoring is carried out until the termination condition is met.

[0046] Notably, the detection unit includes a multi-point pressure sensor, a plasma power detector, a gas chromatograph, and the endpoint detection module. The multi-point pressure sensor is used to collect pressure data from different areas of the vacuum chamber, and the gas chromatograph is used to detect the concentration of reaction products and the concentration of unreacted 3,3,4,4,4-pentafluoro-1-butene at the exhaust port. The gas supply unit includes a 3,3,4,4,4-pentafluoro-1-butene supply unit, a carrier gas supply unit, and an oxygen-containing gas supply unit. The 3,3,4,4,4-pentafluoro-1-butene supply unit includes a vaporizer for vaporizing liquid 3,3,4,4,4-pentafluoro-1-butene before supplying it. The first gas path and the bypass gas path of the cleaning system both include mass flow controllers, and the bypass gas path also includes a valve. The gas transmission channel includes a heating unit for maintaining the pipeline temperature at 30–80°C.

[0047] It is worth emphasizing that the specific process of generating the initial control parameters in step T1 is as follows: the total amount of fluorine-containing active free radicals required is calculated based on the film thickness data, and the cleaning gas flow rate and remote plasma source power are determined in combination with the ionization efficiency of 3,3,4,4,4-pentafluoro-1-butene; the initial values ​​of the pre-vacuum target pressure and the preset cleaning time are determined based on the cavity volume and film type; the control device is configured to open the valve of the bypass gas path 1 to 30 seconds after the activation gas is introduced into the vacuum chamber, so as to achieve the delayed introduction of oxygen-containing gas.

[0048] Example 1

[0049] SiO2 deposition chamber cleaning

[0050] 3,3,4,4,4-Pentafluoro-1-butene volume percentage: 90%

[0051] Inert dilution gas percentage: 10%

[0052] Processing chamber pressure: 8 mbar

[0053] Bypass O2: Injected 15 seconds after the start of step S3, resulting in approximately 6 vol% of inlet O2.

[0054] Pipeline temperature: 70°C

[0055] End point: OES / FTIR

[0056] Result: Residual SiO2 was removed.

[0057] Example 2

[0058] SiN x Deposition chamber cleaning

[0059] 3,3,4,4,4-Pentafluoro-1-butene volume percentage: 80%

[0060] Inert dilution gas percentage: 20%

[0061] Processing chamber pressure: 6 mbar

[0062] Bypass O2: Injected 10 seconds after the start of step S3, so that the inlet N2O is approximately 5 vol%.

[0063] Pipeline temperature: 60°C

[0064] End point: OES / FTIR

[0065] Result: Removal of SiN x Residue.

[0066] In addition, all components designed in this invention are general standard parts or components known to those skilled in the art. Their structure and principle can be known to those skilled in the art through technical manuals or conventional experimental methods. Those skilled in the art can fully implement them, so there is no need to elaborate. The content protected by this invention does not involve improvements to the internal structure and method.

Claims

1. A method for cleaning a remote plasma chamber using 3,3,4,4,4-pentafluoro-1-butene and its control method, characterized in that, The method includes a remote plasma source, a gas supply unit, a vacuum chamber, a vacuum pumping unit, and a bypass gas path, and comprises the following steps: S1. Control the vacuum pumping unit to pre-evacuate the chamber, so that the pressure inside the chamber drops to a preset initial vacuum level; S2. Cleaning gas is supplied to a remote plasma source through the gas supply unit. The cleaning gas has 3,3,4,4,4-pentafluoro-1-butene as its main component, and the volume percentage of 3,3,4,4,4-pentafluoro-1-butene in the cleaning gas is not less than 80%. The temperature of the pipeline used to supply the cleaning gas and oxygen-containing gas is maintained at 30-80°C to suppress condensation. S3. Start the remote plasma source to ionize the cleaning gas to generate fluorine-containing active free radicals. Control the fluorine-containing active free radicals to enter the pre-evacuated vacuum chamber through the gas transmission channel, and contact the silicon-based dielectric deposit on the inner wall of the chamber to undergo a chemical reaction. S4. The remote plasma source is continuously maintained, and oxygen-containing gas is introduced into the vacuum chamber through the bypass gas path, so that the oxygen-containing gas interacts with fluorine-containing active free radicals in the chamber. The bypass gas path bypasses the discharge region of the remote plasma source, and the oxygen-containing gas is introduced after a delay of t seconds after the start of step S3, where t is 1 to 30 seconds. At the same time, the gaseous products generated by the reaction are discharged from the vacuum chamber through the vacuum pumping unit to maintain the preset cleaning time. S5. After cleaning, shut down the remote plasma source and gas supply unit, perform deep evacuation of the vacuum chamber through the vacuum pumping unit, and then introduce inert gas into the chamber to depressurize to atmospheric pressure, thus completing the chamber cleaning.

2. The cleaning method as described in claim 1, characterized in that, The preset initial vacuum level in step S1 is 0.1 mbar to 10 mbar; the preset cleaning time in step S4 is 5 min to 60 min.

3. The cleaning method as described in claim 1, characterized in that, The cleaning gas also includes an inert diluent gas, which is at least one of argon and nitrogen, and the volume percentage of the inert diluent gas in the cleaning gas is 5% to 20%; the oxygen-containing gas is selected from one or more of O2, N2O, and CO2.

4. The cleaning method as described in claim 1, characterized in that, In step S3, the remote plasma source is a radio frequency plasma source or a microwave plasma source with a working power of 200W to 6000W; during step S3, the vacuum chamber pressure is 0.3mbar to 12mbar.

5. The cleaning method as described in claim 1, characterized in that, In step S4, the pressure in the vacuum chamber is maintained between 0.5 mbar and 15 mbar during the reaction process. The pressure in the chamber is stabilized by adjusting the pumping speed of the vacuum pumping unit.

6. A control method for the cleaning method according to any one of claims 1 to 5, characterized in that, The control method includes the following steps: T1: Parameter initialization: Obtain the cavity information and membrane information of the vacuum chamber to be cleaned. The cavity information includes the cavity volume, and the membrane information includes the membrane type and membrane thickness data. Generate initial control parameters based on the cavity information and membrane information. The initial control parameters include the pre-vacuum target pressure, cleaning gas flow rate, remote plasma source power, and preset cleaning time. T2: Process monitoring: The detection unit collects pressure data inside the vacuum chamber, working status data of the remote plasma source, and gas composition data of the exhaust port in real time, and transmits the collected data to the control device in real time. T3: Parameter dynamic adjustment: The pressure data collected in real time is compared with the preset pressure threshold. If the pressure deviation exceeds the allowable range, the pumping speed of the vacuum pumping unit or the cleaning gas flow rate of the gas supply unit is adjusted. At the same time, the reaction process is judged based on the gas composition data of the exhaust port. If the reaction rate is lower than the preset threshold, the working power of the remote plasma source is adjusted. T4: Cleaning Termination Judgment: The endpoint signal output by the endpoint detection module determines whether the cleaning meets the standard. The endpoint detection module is selected from one or more of optical emission spectroscopy (OES), exhaust Fourier transform infrared spectroscopy (FTIR), pressure change detection, or mass spectrometry. When the cleaning endpoint is reached, the cleaning is determined to meet the standard, and the cleaning termination and chamber reset process of step S5 of claim 1 is automatically executed. The cleaning gas supply is also terminated to reduce over-cleaning. If the standard is not met, the cleaning time is extended and continuous monitoring is carried out until the termination condition is met.

7. The control method according to claim 6, characterized in that, The detection unit includes a multi-point pressure sensor, a plasma power detector, a gas chromatograph, and the endpoint detection module. The multi-point pressure sensor is used to collect pressure data in different areas of the vacuum chamber. The gas chromatograph is used to detect the concentration of reaction products and the concentration of unreacted 3,3,4,4,4-pentafluoro-1-butene at the exhaust port. The gas supply unit includes a 3,3,4,4,4-pentafluoro-1-butene supply unit, a carrier gas supply unit, and an oxygen-containing gas supply unit. The 3,3,4,4,4-pentafluoro-1-butene supply unit includes a vaporizer for vaporizing liquid 3,3,4,4,4-pentafluoro-1-butene before supplying it. The first gas path and the bypass gas path of the cleaning system both include mass flow controllers. The bypass gas path also includes a valve. The gas transmission channel includes a heating unit for maintaining the pipeline temperature at 30–80°C.

8. The control method according to claim 6, characterized in that, The specific process of generating initial control parameters in step T1 is as follows: the total amount of fluorine-containing active free radicals required is calculated based on the film thickness data, and the cleaning gas flow rate and remote plasma source power are determined in combination with the ionization efficiency of 3,3,4,4,4-pentafluoro-1-butene; the initial values ​​of the pre-vacuum target pressure and the preset cleaning time are determined based on the cavity volume and film type; the control device is configured to open the valve of the bypass gas path 1 to 30 seconds after the activation gas is introduced into the vacuum chamber, so as to achieve the delayed introduction of oxygen-containing gas.

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