Cleaning apparatus, cleaning method, and semiconductor process device

Abstract

The present application relates to the technical field of semiconductors. Disclosed are a cleaning apparatus, a cleaning method and a semiconductor process device. The semiconductor process device comprises a process chamber, wherein a bearing boat is placed inside the process chamber, the bearing boat comprising inner boat plates and outer boat plates, and the bearing boat having a positive electrode end and a negative electrode end. The cleaning apparatus comprises a first radio-frequency current provision circuit and a second radio-frequency current provision circuit, wherein the first radio-frequency current provision circuit is connected to both the positive electrode end and the negative electrode end, and is used for providing a first radio-frequency current, such that plasma can be generated between the inner boat plates and between the outer boat plates and the inner boat plates adjacent thereto; and the second radio-frequency current provision circuit is connected to both the positive electrode end and the negative electrode end, and is used for providing a second radio-frequency current, such that plasma can be generated between the outer boat plates and a chamber wall of the process chamber, the frequency of the first radio-frequency current being less than the frequency of the second radio-frequency current. In this way, the efficient cleaning of the bearing boat is realized.

Description

Cleaning device, cleaning method and semiconductor process equipment Technical Field

[0001] The present application relates to the field of semiconductor technology, and in particular, to a cleaning device, a cleaning method and semiconductor process equipment. Background Art

[0002] During the production process of photovoltaic solar cells, the graphite boat needs to be cleaned regularly. Existing cleaning methods include wet cleaning.

[0003] Wet cleaning involves tank cleaning with HF / HCl or alkaline solutions. The graphite boat is immersed in a cleaning tank to remove the surface film through a chemical reaction, followed by a long, high-temperature drying process. This method requires disassembly of the graphite boat to achieve a thorough cleaning, and a long, high-temperature drying process is required to remove moisture after cleaning. This results in lengthy cleaning times and increases the risk of breakage. Summary of the Invention

[0004] Embodiments of the present application provide a cleaning device, a cleaning method, and semiconductor process equipment.

[0005] In a first aspect, an embodiment of the present application provides a cleaning device for semiconductor process equipment, wherein the semiconductor process equipment includes a process chamber, wherein a carrier boat is placed in the process chamber, wherein the carrier boat includes an inner boat page and an outer boat page, and the carrier boat has a positive terminal and a negative terminal, and the cleaning device includes a first RF current supply circuit and a second RF current supply circuit, wherein: the first RF current supply circuit is respectively connected to the positive terminal and the negative terminal, and is used to provide a first RF current so that plasma can be generated between the inner boat pages, and between the outer boat page and the inner boat page adjacent thereto; the second RF current supply circuit is respectively connected to the positive terminal and the negative terminal, and is used to provide a second RF current so that plasma can be generated between the outer boat page and the chamber wall of the process chamber, wherein the frequency of the first RF current is less than the frequency of the second RF current.

[0006] In some embodiments, the first RF current providing circuit includes a first RF power supply and a low-pass filter, wherein: one end of the first RF power supply is connected to one end of the low-pass filter; the other end of the first RF power supply is connected to the negative terminal, and the first RF power supply is used to provide a first RF current; the other end of the low-pass filter is connected to the positive terminal, and the low-pass filter is used to allow a first RF current with a frequency lower than a first cut-off frequency to pass through.

[0007] In some embodiments, the second RF current providing circuit includes: a second RF power supply, for providing a second RF current; and a high-pass filtering component, connected to both ends and the positive and negative ends of the second RF power supply, for: allowing the second RF current with a frequency higher than the second cutoff frequency to pass through; and matching the internal impedance of the second RF power supply and the load impedance of the current provided by the second RF power supply.

[0008] In some embodiments, the high-pass filtering component includes: a high-pass filter, one end of the high-pass filter is connected to the positive terminal, and the high-pass filter is used to allow a second RF current with a frequency higher than the second cut-off frequency to pass through; a matcher, connected to the two ends of the second RF power supply, the other end of the high-pass filter and the negative terminal, and is used to match the internal impedance of the second RF power supply and the load impedance of the current provided by the second RF power supply.

[0009] In some embodiments, the frequency of the first radio frequency current ranges from 20 kHz to 400 kHz, and the frequency of the second radio frequency current ranges from 2 MHz to 60 MHz.

[0010] In a second aspect, an embodiment of the present application further provides a cleaning method for cleaning a carrier boat using the above-mentioned cleaning device, the cleaning method comprising: introducing a cleaning gas into a process chamber, regulating the pressure of the process chamber to a preset pressure, and providing a first radio frequency current of a first preset duration to the carrier boat so that the cleaning gas generates plasma between the inner boat pages and between the outer boat page and the adjacent inner boat page; and providing a second radio frequency current of a second preset duration to the carrier boat so that the cleaning gas generates plasma between the outer boat page and the chamber wall of the process chamber.

[0011] In some embodiments, the first preset time and the second preset time are determined according to the cumulative film thickness of the carrier boat during the number of processes and the cleaning rate.

[0012] In some embodiments, the cleaning gas includes at least one of: a fluorine-containing gas and a chlorine-containing gas.

[0013] On the third aspect, an embodiment of the present application also provides a semiconductor process equipment, including a process chamber and the above-mentioned cleaning device, a carrier boat is placed in the process chamber, the carrier boat includes an inner boat page and an outer boat page, the carrier boat has a positive terminal and a negative terminal, and the first RF current providing circuit and the second RF current providing circuit are respectively connected to the positive terminal and the negative terminal.

[0014] In some embodiments, the positive terminal includes a positive electrode hole, the negative terminal includes a negative electrode hole, and the first RF current providing circuit and the second RF current providing circuit are respectively connected to the positive electrode hole and the negative electrode hole through the electrode rod; or the positive terminal includes a positive electrode boat pin, the negative terminal includes a negative electrode boat pin, and the first RF current providing circuit and the second RF current providing circuit are respectively connected to the positive electrode boat pin and the negative electrode boat pin through overlapping.

[0015] Through the above technical solution, plasma can be generated between the inner boat pages of the carrier boat, and between the outer boat page and the adjacent inner boat page to clean the inner sides of the inner boat page and the outer boat page, and plasma can also be generated between the outer boat page of the carrier boat and the chamber wall of the process chamber to clean the outer side of the outer boat page, thus achieving efficient cleaning of the carrier boat. In addition, when cleaning the carrier boat, there is no need to disassemble the carrier boat, and there is no need to dry it at high temperature for a long time to remove water vapor, which reduces the cleaning time and the risk of the carrier boat breaking. In addition, when cleaning the carrier boat, the cleaning gas is introduced into the process chamber, and plasma is formed between the inner boat pages of the carrier boat, between the outer boat page and the adjacent inner boat page, and between the outer boat page of the carrier boat and the chamber wall of the process chamber. There is no need to use a large amount of cleaning gas to pass the plasma into the process chamber, and the life of the plasma is not limited by the transportation distance, which reduces the cleaning cost and achieves relatively uniform cleaning of the carrier boat.

[0016] Other features and advantages of the present application will be described in detail in the following specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings are used to provide a further understanding of the present application and constitute a part of the specification. Together with the following detailed description, they are used to explain the present application but do not constitute a limitation of the present application. In the accompanying drawings:

[0018] FIG1 is a schematic diagram of a cleaning device for semiconductor process equipment provided by one embodiment of the present application;

[0019] FIG2 is a schematic diagram of a graphite boat provided in another embodiment of the present application;

[0020] FIG3 is an equivalent circuit of a graphite boat mixer for cleaning provided by another embodiment of the present application;

[0021] FIG4a is a schematic diagram of the ignition position when the low-frequency RF power supply is turned on according to another embodiment of the present application;

[0022] FIG4 b is a schematic diagram of the ignition position when the high-frequency RF power supply is turned on according to another embodiment of the present application;

[0023] FIG5 is a flow chart of a cleaning method provided by another embodiment of the present application; and

[0024] FIG6 is a flow chart of a cleaning method provided in another embodiment of the present application. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0026] Plasma cleaning can be used to clean graphite boats. Plasma cleaning includes remote plasma cleaning and in-situ plasma cleaning.

[0027] Remote plasma cleaning is to equip a remote plasma source outside the reaction chamber, and ionize the cleaning gas and then pass it into the reaction chamber to achieve the cleaning purpose. When performing remote plasma cleaning, the farther the graphite boat is from the air flow inlet, the worse the cleaning effect. Generally, the transmission distance of the remote plasma system (RPS) is 50cm-60cm, and the actual length of the graphite boat is 280cm, which makes the cleaning rate of the position of the graphite boat close to the air inlet pipe higher and the cleaning rate of the position far from the air inlet pipe lower, resulting in uneven cleaning. In addition, when remote plasma cleaning is used, the gas usage is high; because the membrane layer of the graphite boat to be cleaned is thicker, this cleaning method will reduce the cleaning efficiency and increase the cleaning cost. Therefore, when remote plasma cleaning is used, the gas usage is high and the plasma life is limited by the transportation distance, which leads to high remote plasma cleaning costs and uneven cleaning of the graphite boat.

[0028] In-situ plasma cleaning primarily involves introducing electrodes into the reaction chamber, igniting them between the graphite boat sheets, ionizing the cleaning gas to form a plasma, and causing the active particles in the plasma to react with the film layer to produce volatile substances, thereby achieving the purpose of cleaning the graphite boat. However, traditional tubular plasma-enhanced chemical vapor deposition (PECVD) equipment generally uses a low-frequency (20kHz to 400kHz) power supply, and the ignition location is only between the inner boat sheets of the graphite boat, and between the outer boat sheet and the adjacent inner boat sheet. Therefore, when using in-situ plasma cleaning, the cleaning effect of the outer boat sheets of the graphite boat is poor, ultimately resulting in a long cleaning time for the entire graphite boat and increased cleaning costs.

[0029] How to clean the graphite boat efficiently has become an urgent problem to be solved in this field.

[0030] In the first aspect, an embodiment of the present application provides a cleaning device for semiconductor process equipment, wherein the semiconductor process equipment includes a process chamber, wherein a carrier boat is placed in the process chamber, wherein the carrier boat includes an inner boat page and an outer boat page, and wherein the carrier boat has a positive terminal and a negative terminal, which can realize efficient cleaning of the carrier boat.

[0031] In the embodiments of the present application, the inner and outer boat pages may be collectively referred to as boat pages. The outer boat pages are arranged outside the inner boat pages, and the boat pages are alternately connected to the positive and negative terminals. Furthermore, in some embodiments, the positive terminal may be a positive electrode hole. In some embodiments, the negative terminal may be a negative electrode hole. In some embodiments, the carrier boat may be a graphite boat. In some embodiments, the process chamber may be a quartz tube.

[0032] In one embodiment of the present application, the cleaning device may include a first RF current supply circuit and a second RF current supply circuit, wherein: the first RF current supply circuit is respectively connected to the positive terminal and the negative terminal, and is used to provide a first RF current so that plasma can be generated between the inner boat pages, and between the outer boat page and the adjacent inner boat page; the second RF current supply circuit is respectively connected to the positive terminal and the negative terminal, and is used to provide a second RF current so that plasma can be generated between the outer boat page and the chamber wall of the process chamber, wherein the frequency of the first RF current is less than the frequency of the second RF current.

[0033] In the embodiment of the present application, the cleaning gas can be determined according to the substance to be cleaned on the carrier boat, as long as it can chemically react with the substance to be cleaned to remove the substance to be cleaned. In addition, the cleaning gas can also include some gases that can assist in ignition.

[0034] The technical solution provided by the embodiment of the present application can generate plasma between the inner boat pages of the carrier boat, and between the outer boat page and the adjacent inner boat page to clean the inner boat pages and the inner side of the outer boat page, and can also generate plasma between the outer boat page of the carrier boat and the chamber wall of the process chamber to clean the outer side of the outer boat page, thus achieving efficient cleaning of the carrier boat. In addition, when cleaning the carrier boat, there is no need to disassemble the carrier boat, and there is no need to dry it at high temperature for a long time to remove water vapor, which reduces the cleaning time and the risk of the carrier boat breaking. In addition, when cleaning the carrier boat, the cleaning gas is introduced into the process chamber, and plasma is formed between the inner boat pages of the carrier boat, between the outer boat page and the adjacent inner boat page, and between the outer boat page of the carrier boat and the chamber wall of the process chamber. There is no need to use a large amount of cleaning gas due to the introduction of plasma into the process chamber, and the life of the plasma is not limited by the transportation distance, which reduces the cleaning cost and achieves relatively uniform cleaning of the carrier boat. In addition, the technical solution provided in the embodiment of the present application can generate plasma between the inner boat pages and between the outer boat page and the adjacent inner boat page to clean the inner sides of the inner boat pages and the outer boat pages, and can also generate plasma between the outer boat page and the chamber wall of the process chamber to clean the outer sides of the outer boat pages, thereby improving the cleaning effect of the outer boat pages, reducing the overall cleaning time of the carrier boat, and reducing the cleaning cost.

[0035] Furthermore, in an embodiment of the present application, the first RF current supply circuit may include a first RF power supply and a low-pass filter. One end of the first RF power supply is connected to one end of the low-pass filter; the other end of the first RF power supply is connected to the negative terminal, and the first RF power supply is configured to provide the first RF current. The other end of the low-pass filter is connected to the positive terminal, and the low-pass filter is configured to allow RF current with a frequency lower than a first cutoff frequency to pass through. The first cutoff frequency is greater than the frequency of the first RF current. In other words, the low-pass filter is configured to allow the first RF current with a frequency lower than the first cutoff frequency to pass through.

[0036] Furthermore, in an embodiment of the present application, the second RF current providing circuit may include a second RF power supply and a high-pass filter component. The second RF power supply is used to provide a second RF current. The high-pass filter component is connected to both ends of the second RF power supply and the positive terminal and the negative terminal. The high-pass filter component is used to allow RF current with a frequency higher than a second cutoff frequency to pass through, and the second cutoff frequency is lower than the frequency of the second RF current. In other words, the high-pass filter component allows the second RF current with a frequency higher than the second cutoff frequency to pass through. In addition, the high-pass filter component is also used to match the internal impedance of the second RF power supply and the load impedance of the current provided by the second RF power supply. The load impedance may include the resistance of the outer boat page, the resistance of the chamber wall of the process chamber, and the resistance on the connection line from the second RF power supply to the positive terminal and the negative terminal.

[0037] Furthermore, in an embodiment of the present application, the high-pass filtering component may include a high-pass filter and a matching device. One end of the high-pass filter is connected to the positive terminal, and is configured to allow the passage of a second RF current having a frequency higher than a second cutoff frequency. The matching device is connected to both ends of the second RF power supply, the other end of the high-pass filter, and the negative terminal, and is configured to match the internal impedance of the second RF power supply with the load impedance of the current provided by the second RF power supply.

[0038] Furthermore, in the embodiment of the present application, the frequency of the first radio frequency current ranges from 20 kHz to 400 kHz, and the frequency of the second radio frequency current ranges from 2 MHz to 60 MHz.

[0039] Figure 1 is a schematic diagram of a cleaning apparatus for semiconductor processing equipment according to one embodiment of the present application. The cleaning apparatus is used to clean a graphite boat in a PECVD device. In this embodiment, the process chamber is a quartz tube 6, the first RF power supply for providing a first RF current is a low-frequency RF power supply 11, and the second RF power supply for providing a second RF current is a high-frequency RF power supply 14.

[0040] As shown in Figure 1, the cleaning device primarily comprises a low-frequency RF power supply 11, a high-frequency RF power supply 14, a matching element 13, a low-pass filter 10, and a high-pass filter 12. A graphite boat 7 is placed in a quartz tube 6. The quartz tube 6 includes an inlet and an outlet. Cleaning gas enters the quartz tube 6 through the inlet, and the outlet is connected to a dry pump 9. The positive terminal of the low-frequency RF power supply 11 is connected to the low-pass filter 10; the negative terminal of the low-frequency RF power supply 11 is connected to the second RF electrode rod 17 via a wire, which is then connected to the negative electrode hole of the graphite boat 7; the negative terminal of the low-frequency RF power supply 11 is grounded. The low-pass filter 10 is connected to the positive terminal of the low-frequency RF power supply 11 and to the positive electrode hole of the graphite boat 7 via a wire and the first RF electrode rod 8. The matching element 13 is connected to the positive and negative terminals of the high-frequency RF power supply 14 and one end of the high-pass filter 12, and is also connected to the negative electrode hole of the graphite boat 7 via a wire and the RF electrode rod 17. One end of the high-pass filter 12 is connected to the matching device 13 , and the other end is connected to the positive electrode hole of the graphite boat 7 through a wire and the first radio frequency electrode rod 8 .

[0041] The low-frequency RF power supply 11 and the high-frequency RF power supply 14 are each used to feed an electric field into the graphite boat 7 to generate plasma. The high-frequency RF power supply 14 provides high-frequency RF current to the graphite boat 7 via a matching device 13. The matching device 13 is used to achieve impedance matching between the high-frequency RF power supply 14 and the load. The load includes all components to which the high-frequency RF power supply 14 can provide current. For example, the load may include the outer sheets of the graphite boat, the walls of the quartz tube, and the connecting wires from the high-frequency RF power supply 14 to the positive and negative electrode holes of the graphite boat 7. The low-pass filter 10 only allows low-frequency waves to pass, while the high-pass filter 12 only allows high-frequency waves to pass. The positive terminal of the low-frequency RF power supply 11 is connected to the low-pass filter 10, and the high-frequency RF power supply 14 is connected to the matching device 13 and then connected to the high-pass filter 12. The high-pass filter 12 and the low-pass filter 10 are connected to the first RF electrode rod 8, which is then connected to the graphite boat 7, ultimately introducing the RF power to the graphite boat 7.

[0042] Traditional tubular PECVD equipment typically uses a low-frequency RF power source 11 in the 20kHz to 400kHz range. When cleaning gas is introduced, ignition occurs only between the inner sheets of the graphite boat and between the outer sheet and its adjacent inner sheet. This results in a higher cleaning rate only on the inner and outer sheets of the graphite boat, while the cleaning rate on the outer side of the outer sheet is much lower than on the inner and outer sheets. The inner and outer sheets 16 and 15 of the graphite boat are shown in FIG2 .

[0043] In the technical solution provided in the embodiments of the present application, a mixing circuit design is employed, as shown in FIG3 . This allows a low-frequency RF power supply 11 to provide a low-frequency RF current to the graphite boat, and a high-frequency RF power supply 14 to provide a high-frequency RF current to the graphite boat. When the low-frequency RF power supply 11 is turned on, plasma is generated between the inner boat pages 16 of the graphite boat, and between the outer boat pages and the adjacent inner boat pages (as shown in FIG4 a , plasma is formed between the inner boat pages and between the outer boat pages and the adjacent inner boat pages), forming loop 1. When the high-frequency RF power supply 14 is turned on, the plasma is generated between the outer boat pages 15 of the graphite boat and the wall of the quartz tube 6 (as shown in FIG4 b , plasma is formed between the outer boat pages and the wall of the quartz tube), forming loop 2.

[0044] The outer boat pages of the graphite boat and the wall of the quartz tube, the inner boat pages of the graphite boat and the inner boat pages (only one inner boat page 16 is shown in Figure 3, it should be noted that the graphite boat has multiple inner boat pages 16), and the outer boat pages and the adjacent inner boat pages are equivalent to capacitors. The impedance of the capacitor is x = 1 / (2πjfc), where f represents the frequency of the power supply and c represents the capacitance value of the capacitor.

[0045] When the frequency f of the power supply is very low, the capacitor is equivalent to a short circuit and no plasma is generated. No path can be formed between the outer boat page and the wall of the quartz tube, between the inner boat pages, and between the outer boat page and the adjacent inner boat page.

[0046] When low-frequency power is applied (that is, when low-frequency RF power source 11 is turned on), the electric field strength between the inner boats is greater, and plasma is generated only between the inner boats and between the outer boat and its adjacent inner boat. Therefore, loop 1 is conductive. Furthermore, the circuit between the outer boat and the wall of the quartz tube remains open.

[0047] When high-frequency power is applied, that is, when high-frequency RF power source 14 is turned on, the low impedance eliminates the circuits between the quartz tube wall and the outer sheets, between the inner sheets, and between the outer sheets and adjacent inner sheets. Loops 1 and 2 both constitute RF loops. The capacitance between the outer sheets and the quartz tube wall is much greater than the capacitance between the inner sheets and between the outer sheets and adjacent inner sheets. Therefore, the impedance between the outer sheets and the quartz tube wall is much lower than the impedance between the inner sheets and between the outer sheets and adjacent inner sheets. In other words, the impedance of loop 2 is much lower than that of loop 1, and the majority of the RF power is distributed in loop 2. The electric field strength between the outer sheets and the quartz tube wall is much greater than the electric field strength between the inner sheets and between the outer sheets and adjacent inner sheets. Therefore, plasma is more likely to form between the outer sheets and the quartz tube wall.

[0048] In the technical solution provided in the embodiment of the present application, the low-frequency RF power supply or the high-frequency RF power supply can be controlled to be turned on by the host computer.

[0049] Furthermore, in the embodiment of the present application, the low-frequency RF power source 11 can be controlled to be on for a first preset duration. The first preset duration can be calculated based on the accumulated film thickness of the first graphite boat process times and the first cleaning rate (etching rate).

[0050] Furthermore, in the embodiment of the present application, the high frequency RF power source 14 can be controlled to be on for a second preset duration. The second preset duration can be calculated based on the accumulated film thickness of the second graphite boat process times and the second cleaning rate (etching rate).

[0051] Furthermore, in the embodiment of the present application, the frequency of the low-frequency RF power source 11 may be in the range of 20 kHz to 400 kHz, and the frequency of the high-frequency RF power source 14 may be in the range of 2 MHz to 60 MHz.

[0052] Furthermore, in embodiments of the present application, the cleaning gas may include at least one of a fluorine-containing gas and a chlorine-containing gas. In some embodiments, the cleaning gas may also include at least one of Ar and O2 to assist in ignition. Preferably, the fluorine-containing gas may include at least one of NF3, SF6, CF4, and F2. Preferably, the chlorine-containing gas may include at least one of Cl2 and HCl.

[0053] In this embodiment, a mixing circuit design is employed to address the unique structure of the graphite boat. A low-frequency RF power supply 11 is used to generate plasma between the inner and outer pages of the graphite boat, as well as between the outer and adjacent inner pages, to clean the inner and outer pages. A high-frequency RF power supply 14 is used to generate plasma between the chamber wall and the outer pages of the graphite boat, to clean the outer sides of the outer pages. This allows for rapid, seamless cleaning of the graphite boat.

[0054] Conventional wet cleaning of SiNx graphite boats requires approximately 12 hours of cleaning, 10 hours of drying, and 3 hours of boat coating. Using only traditional low-frequency RF power for cleaning provides high efficiency on the inner boat, but slow cleaning of the outer boat results in poor cleaning results. This ultimately results in a long overall cleaning time of 4-6 hours, increasing cleaning costs.

[0055] In an embodiment of the present application, a mixing circuit design is adopted to control the ignition between the inner boat pages and the inner boat pages and between the outer boat pages and the adjacent inner boat pages to achieve the purpose of cleaning the inner sides of the inner and outer boat pages, and to control the ignition between the chamber wall of the chamber and the outer boat pages of the graphite boat to achieve the purpose of cleaning the outer sides of the outer boat pages. The technical solution provided by the embodiment of the present application can ensure the cleaning effect of the inner and outer boat pages without disassembling the graphite boat, and does not require high-temperature drying and removal of water vapor, which reduces the cleaning time and reduces the risk of graphite boat breakage. The technical solution provided by the embodiment of the present application can ensure the cleaning effect of the inner and outer boat pages, improve the cleaning effect of the outer boat pages, and increase the etching rate of the outer boat pages. In addition, the technical solution provided by the embodiment of the present application forms plasma between the inner boat pages of the graphite boat and between the outer boat pages of the graphite boat and the chamber wall of the chamber, which improves the phenomenon of incomplete and uneven cleaning of the graphite boat. It has been verified that the technical solution provided in the embodiment of the present application only takes 2 to 3 hours to clean, which shortens the overall cleaning time of the graphite boat, reduces costs, ensures the stability of process performance, and increases equipment production capacity.

[0056] In a second aspect, an embodiment of the present application provides a cleaning method for cleaning a carrier boat using the cleaning device described in the above embodiment.

[0057] FIG5 is a flow chart of a cleaning method provided by another embodiment of the present application. As shown in FIG5 , the cleaning method includes the following contents:

[0058] In step S50, a cleaning gas is introduced into the process chamber, the pressure of the process chamber is adjusted to a preset pressure, and a first radio frequency current of a first preset duration is provided to the carrier boat so that the cleaning gas generates plasma between the inner boat pages and between the outer boat page and the adjacent inner boat page.

[0059] In step S51 , a second radio frequency current of a second predetermined duration is provided to the carrier boat, so that the cleaning gas generates plasma between the outer boat page and the chamber wall of the process chamber.

[0060] It should be noted that FIG5 and the explanation based on FIG5 are merely exemplary explanations of the cleaning method provided in the embodiments of the present application and are not intended to limit the order of the steps. In other words, in the embodiments of the present application, plasma may be first formed between the inner boat pages and between the outer boat pages and the adjacent inner boat pages, and then plasma may be formed between the outer boat pages and the chamber walls. Alternatively, plasma may be first formed between the outer boat pages and the chamber walls, and then plasma may be formed between the inner boat pages and between the outer boat pages and the adjacent inner boat pages.

[0061] Furthermore, in an embodiment of the present application, the first preset time and the second preset time are determined based on the cumulative film thickness and the cleaning rate of the carrier boat during the number of processes. In some embodiments, the cleaning rate may be an etching rate. In other words, the first preset time and the second preset time can be determined based on the cumulative film thickness and the etching rate of the carrier boat during the number of processes. The first preset time is determined based on the cumulative film thickness and the first etching rate of the film layer between the inner boat pages to be cleaned, and between the outer boat page and the adjacent inner boat page, during the first number of processes. The second preset time is determined based on the cumulative film thickness and the second etching rate of the film layer between the outer boat page to be cleaned and the chamber wall of the process chamber during the second number of processes.

[0062] FIG6 is a flow chart of a cleaning method provided in another embodiment of the present application. The cleaning method provided in the embodiment of the present application is exemplarily explained below with reference to FIG6. In this embodiment, the carrier boat is a graphite boat. The cleaning method includes:

[0063] In step S60 , the graphite boat to be cleaned is transferred to a process chamber, and a radio frequency electrode (eg, an electrode rod) is connected to the electrode holes on the graphite boat, so that both the positive electrode hole and the negative electrode hole of the graphite boat are connected to a radio frequency electrode.

[0064] In step S61, the graphite boat is returned to the process temperature and the process chamber is evacuated. The process temperature may be between 200°C and 220°C.

[0065] In step S62, a cleaning gas is introduced into the process chamber, the pressure in the process chamber is adjusted to a first pressure, and the low-frequency RF power supply is turned on and maintained for a first preset time. The cleaning gas may include at least one of a fluorine-containing gas and a chlorine-containing gas. In some embodiments, the cleaning gas may also include at least one of Ar and O2 to assist in ignition. Preferably, the fluorine-containing gas may include at least one of NF3, SF6, CF4, and F2. Preferably, the chlorine-containing gas includes at least one of Cl2 and HCl. The first preset time can be calculated based on the cumulative film thickness of the first graphite boat process number and the first etching rate. Specifically, the first preset time can be obtained by dividing the cumulative film thickness of the first graphite boat process number by the first etching rate. The frequency of the low-frequency RF power supply can range from 20KHz to 400KHz. Specifically, the frequency of the low-frequency RF power supply can be 40KHz. Specifically, the cleaning gas includes SF6 and Ar. Furthermore, the first pressure can be 0.5 Torr to 1 Torr, the SF6 flow rate can be 6000 sccm to 9000 sccm, and the Ar flow rate can be 2000 sccm to 3000 sccm. The low-frequency RF power supply is turned on for a first predetermined duration to completely clean the film between the inner boat pages of the graphite boat, and between the outer boat page and the adjacent inner boat page.

[0066] In step S63, after reaching the first preset time, the low-frequency RF power supply is turned off. The pressure in the process chamber is adjusted to the second pressure. The high-frequency RF power supply is turned on and controlled to last for a second preset time. The second preset time is calculated based on the cumulative film thickness of the second graphite boat process times and the second etching rate. Specifically, the second preset time can be obtained by dividing the cumulative film thickness of the second graphite boat process times by the second etching rate. The frequency of the high-frequency RF power supply can range from 2MHz to 60MHz. Specifically, the frequency of the high-frequency RF power supply is 13.56MHz. The on time of the high-frequency RF power supply is controlled to last for the second preset time, so as to 100% clean the film layer at the outer boat page of the graphite boat and the film layer at the boat foot. In an embodiment of the present application, the first pressure and the second pressure can be determined according to the specific circumstances.

[0067] In addition, in an embodiment of the present application, in addition to controlling the on-time of the low-frequency RF power supply and the high-frequency RF power supply respectively by setting a first preset time length and a second preset time length, the on-time of the low-frequency RF power supply and the on-time of the high-frequency RF power supply can also be controlled by adding a gas composition analyzer to analyze whether there are still components in the film layer deposited on the graphite boat in the process chamber.

[0068] In step S64 , when the second preset time is reached, the high frequency radio frequency power supply is turned off, and N 2 or Ar is introduced into the chamber to purge the chamber to blow away the cleaning gas.

[0069] In step S65, after the graphite boat is cleaned, the chamber is backfilled with N2 or Ar to return the process chamber to atmospheric pressure. The boat is then unloaded. In some embodiments, the N2 or Ar purge flow rate can be 10,000 sccm to 50,000 sccm.

[0070] It should be noted that Figure 6 and the explanation based on Figure 6 are exemplary illustrations of the cleaning method provided in the embodiments of the present application and are not intended to limit the present application. In the embodiments of the present application, the low-frequency RF power supply can be turned on first and then the high-frequency RF power supply, or the high-frequency RF power supply can be turned on first and then the low-frequency RF power supply.

[0071] The film layer on the surface of the graphite boat to be cleaned includes intrinsic amorphous silicon, phosphorus / boron-doped amorphous silicon, intrinsic polycrystalline silicon, and phosphorus / boron-doped polycrystalline silicon. The PECVD equipment involved in the embodiments of this application can be a tubular PECVD equipment for heterojunction solar cells. During the PECVD deposition of the amorphous silicon thin film for heterojunction solar cells, an amorphous silicon film layer is deposited on the graphite boat. When the film layer reaches a predetermined thickness, it is cleaned using the cleaning method provided in the embodiments of this application. The predetermined thickness can be determined based on the specific circumstances.

[0072] In a third aspect, an embodiment of the present application provides a semiconductor process equipment, comprising a process chamber and the cleaning device described in the above embodiments, wherein a carrier boat is placed in the process chamber, the carrier boat comprising an inner boat page and an outer boat page, the carrier boat having a positive terminal and a negative terminal, and a first RF current providing circuit and a second RF current providing circuit are respectively connected to the positive terminal and the negative terminal.

[0073] Furthermore, in an embodiment of the present application, the positive terminal includes a positive electrode hole, the negative terminal includes a negative electrode hole, and the first RF current providing circuit and the second RF current providing circuit are respectively connected to the positive electrode hole and the negative electrode hole through electrode rods.

[0074] Furthermore, in an embodiment of the present application, the positive terminal includes a positive electrode boat pin, the negative terminal includes a negative electrode boat pin, and the first RF current supply circuit and the second RF current supply circuit are respectively connected to the positive electrode boat pin and the negative electrode boat pin by a bridging manner. Specifically, the bridging can be performed by an electrode rod and a bridging member.

[0075] In a fourth aspect, an embodiment of the present application further provides a storage medium having a computer program stored thereon. When the computer program is executed by a processor, the cleaning method described in the above embodiment is implemented.

[0076] In a fifth aspect, an embodiment of the present application further provides a computer program product, which includes computer program instructions. When the computer program instructions are executed by a processor, the processor executes the steps of the cleaning method described in the above embodiment.

[0077] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0078] The above embodiments merely represent several implementation methods of this specification. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of this specification, and these modifications and improvements fall within the scope of protection of this specification. Therefore, the scope of protection of the patent in this specification shall be based on the appended claims.

Claims

1. A cleaning device for semiconductor process equipment, characterized in that: The semiconductor process equipment comprises a process chamber, a carrier boat is placed in the process chamber, the carrier boat comprises an inner boat page and an outer boat page, the carrier boat has a positive terminal and a negative terminal, and the cleaning device comprises a first radio frequency current supply circuit and a second radio frequency current supply circuit, wherein: The first radio frequency current supply circuit is connected to the positive terminal and the negative terminal respectively, and is used to provide a first radio frequency current so as to generate plasma between the inner boat pages and between the outer boat page and the inner boat page adjacent thereto; The second RF current providing circuit is connected to the positive terminal and the negative terminal respectively, and is used to provide a second RF current so that plasma can be generated between the outer boat page and the chamber wall of the process chamber, wherein the frequency of the first RF current is less than the frequency of the second RF current.

2. The cleaning device according to claim 1, characterized in that: The first radio frequency current providing circuit comprises a first radio frequency power supply and a low-pass filter, wherein: One end of the first RF power supply is connected to one end of the low-pass filter; the other end of the first RF power supply is connected to the negative terminal, and the first RF power supply is used to provide a first RF current; The other end of the low-pass filter is connected to the positive terminal, and the low-pass filter is used to allow the first radio frequency current having a frequency lower than a first cut-off frequency to pass through.

3. The cleaning device according to claim 1, characterized in that: The second radio frequency current providing circuit comprises: A second RF power supply, configured to provide the second RF current; and A high-pass filter component is connected to both ends of the second RF power source and the positive terminal and the negative terminal, and is used for: allowing the second radio frequency current having a frequency higher than a second cut-off frequency to pass; and The internal impedance of the second RF power source and the load impedance to which the current is provided by the second RF power source are matched.

4. The cleaning device according to claim 3, characterized in that: The high-pass filtering component comprises: a high-pass filter, one end of which is connected to the positive terminal, and the high-pass filter is used to allow the second radio frequency current having a frequency higher than the second cut-off frequency to pass through; A matcher is connected to two ends of the second RF power supply, the other end of the high-pass filter and the negative terminal, and is used to match the internal impedance of the second RF power supply with the load impedance of the current provided by the second RF power supply.

5. The cleaning device according to claim 1, characterized in that: The frequency of the first radio frequency current ranges from 20 KHz to 400 KHz, and the frequency of the second radio frequency current ranges from 2 MHz to 60 MHz.

6. A method for cleaning a carrier boat using the cleaning device according to any one of claims 1 to 5, characterized in that: The cleaning method comprises: Introducing a cleaning gas into the process chamber, adjusting the pressure of the process chamber to a preset pressure, and providing a first radio frequency current of a first preset duration to the carrier boat, so that the cleaning gas generates plasma between the inner boat pages and between the outer boat page and the inner boat page adjacent thereto; and A second radio frequency current of a second preset duration is provided to the carrier boat, so that the cleaning gas generates plasma between the outer boat page and the chamber wall of the process chamber.

7. The cleaning method according to claim 6, characterized in that: The first preset time length and the second preset time length are determined according to the cumulative film thickness and the cleaning rate of the carrier boat after the number of processes.

8. The cleaning method according to claim 6, characterized in that: The cleaning gas includes at least one of the following: a fluorine-containing gas and a chlorine-containing gas.

9. A semiconductor process equipment, characterized in that: It comprises a process chamber and a cleaning device as described in any one of claims 1 to 5, wherein a carrier boat is placed in the process chamber, the carrier boat comprises an inner boat page and an outer boat page, the carrier boat has a positive terminal and a negative terminal, and a first RF current providing circuit and a second RF current providing circuit are respectively connected to the positive terminal and the negative terminal.

10. The semiconductor process equipment according to claim 9, characterized in that: The positive terminal includes a positive electrode hole, the negative terminal includes a negative electrode hole, and the first radio frequency current supply circuit and the second radio frequency current supply circuit are respectively connected to the positive electrode hole and the negative electrode hole through electrode rods; or The positive terminal includes a positive boat pin, the negative terminal includes a negative boat pin, and the first radio frequency current providing circuit and the second radio frequency current providing circuit are respectively connected to the positive boat pin and the negative boat pin by overlapping.

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