阅读说明：本技术 用于pecvd设备的原位清洗方法及对应的pecvd设备 (In-situ cleaning method for PECVD (plasma enhanced chemical vapor deposition) equipment and corresponding PECVD equipment ) 是由 吴科俊 张津燕 马哲国 陈金元 于 2020-07-30 设计创作，主要内容包括：本发明提供用于PECVD设备的原位清洗方法及相应的PECVD设备。所述方法包括：第一步骤,向PECVD设备的反应腔室通入含氟清洗气体并将其压强调节至第一压强,开启射频发生器并持续第一预设时间；第二步骤,持续通入含氟清洗气体并将反应腔室压强调节至第二压强,保持射频发生器持续开启第二预设时间；第三步骤,持续通入含氟清洗气体并将其压强调节至第三压强,保持射频发生器持续开启第三预设时间；第四步骤,持续通入含氟清洗气体并将其压强调节至第四压强,保持射频发生器持续开启第四预设时间；以及第五步骤,持续通入含氟清洗气体并将其压强调节至第五压强,保持射频发生器持续开启第五预设时间；其中第一至第五压强依次减小。本发明能有效提高清洗效率。(The invention provides an in-situ cleaning method for PECVD equipment and corresponding PECVD equipment. The method comprises the following steps: the method comprises the following steps that firstly, fluorine-containing cleaning gas is introduced into a reaction chamber of PECVD equipment, the pressure of the fluorine-containing cleaning gas is adjusted to a first pressure, and a radio frequency generator is started and is continued for a first preset time; continuously introducing fluorine-containing cleaning gas, adjusting the pressure of the reaction chamber to a second pressure, and keeping the radio frequency generator continuously started for a second preset time; a third step of continuously introducing the fluorine-containing cleaning gas, adjusting the pressure of the fluorine-containing cleaning gas to a third pressure, and keeping the radio frequency generator continuously started for a third preset time; step four, continuously introducing fluorine-containing cleaning gas, adjusting the pressure of the fluorine-containing cleaning gas to a fourth pressure, and keeping the radio frequency generator continuously started for a fourth preset time; and a fifth step of continuously introducing the fluorine-containing cleaning gas, adjusting the pressure of the fluorine-containing cleaning gas to a fifth pressure, and keeping the radio frequency generator continuously started for a fifth preset time; wherein the first to fifth pressures are reduced in sequence. The invention can effectively improve the cleaning efficiency.)

1. A method for in situ cleaning of a PECVD apparatus comprising a reaction chamber and a radio frequency generator, the method comprising the steps of:

the method comprises the following steps that firstly, fluorine-containing cleaning gas is introduced into a reaction chamber, the pressure of the reaction chamber is adjusted to a first pressure, and a radio frequency generator is started and is kept for a first preset time;

a second step of continuously introducing fluorine-containing cleaning gas into the reaction chamber, adjusting the pressure of the reaction chamber to a second pressure, and keeping the radio frequency generator continuously started for a second preset time;

a third step of continuously introducing fluorine-containing cleaning gas into the reaction chamber, adjusting the pressure of the reaction chamber to a third pressure, and keeping the radio frequency generator continuously started for a third preset time;

a fourth step of continuously introducing fluorine-containing cleaning gas into the reaction chamber, adjusting the pressure of the reaction chamber to a fourth pressure, and keeping the radio frequency generator continuously started for a fourth preset time; and

a fifth step of continuously introducing fluorine-containing cleaning gas into the reaction chamber, adjusting the pressure of the reaction chamber to a fifth pressure, and keeping the radio frequency generator continuously started for a fifth preset time;

wherein the first pressure, the second pressure, the third pressure, the fourth pressure and the fifth pressure are reduced from large to small in sequence.

2. The in-situ cleaning method according to claim 1, wherein the first pressure is 0.55mbar to less than 0.65mbar, the second pressure is 0.45mbar to less than 0.55mbar, and the third pressure is 0.35mbar to less than 0.45 mbar; the fourth pressure is 0.25mbar to less than 0.35 mbar; the fifth pressure is 0.15mbar to less than 0.25 mbar.

3. The in-situ cleaning method according to claim 1, wherein in the first step to the fifth step, a fluorine-containing cleaning gas is ionized into a fluorine-containing plasma by the radio frequency generator, the fluorine-containing plasma reacts with the silicon film layer covering the inner wall of the reaction chamber and the surface of the carrier plate arranged in the reaction chamber, and the sum of the areas of the inner wall of the reaction chamber and the surface of the carrier plate is not less than 500mm x 500 mm; the silicon film layer comprises intrinsic polycrystalline silicon, intrinsic amorphous silicon, phosphorus/boron doped polycrystalline silicon, phosphorus/boron doped amorphous silicon, a silicon carbon film and a silicon oxygen film.

4. The in-situ cleaning method according to claim 3, wherein in the second step, the fluorine-containing plasma covers the inner wall of the reaction chamber and the surface of the support plate for 60% to less than 70% of the total area of the inner wall and the surface of the support plate after the first and second predetermined times, and the flow rate of the fluorine-containing cleaning gas and the power of the RF generator in the first step are correspondingly the same as those in the second step.

5. The in-situ cleaning method according to claim 4, wherein in the third step, the fluorine-containing plasma covers the inner wall of the reaction chamber and the surface of the support plate for 70% to less than 85% of the total area of the inner wall and the surface of the support plate after the first predetermined time, the second predetermined time and the third predetermined time, and the flow rate of the fluorine-containing cleaning gas and the power of the RF generator in the second step are correspondingly the same as those in the third step.

6. The in-situ cleaning method according to claim 5, wherein in the fourth step, the fluorine-containing plasma covers the inner wall of the reaction chamber and the surface of the support plate for 85% to less than 100% of the total area after the first preset time, the second preset time, the third preset time and the fourth preset time, and the flow rate of the fluorine-containing cleaning gas and the power of the RF generator in the third step are the same or different from the flow rate of the fluorine-containing cleaning gas and the power of the RF generator in the fourth step.

7. The in-situ cleaning method according to claim 6, wherein in the fifth step, the fluorine-containing plasma cleans the inner wall of the reaction chamber and the surface of the carrier plate with 100% total coverage, and the flow rate of the fluorine-containing cleaning gas and the power of the RF generator in the fourth step are the same or different from those in the fifth step.

8. The in-situ cleaning method according to claim 1, wherein the first preset time, the second preset time, the third preset time, the fourth preset time and the fifth preset time are all the same, or at least two of the first preset time, the second preset time, the third preset time, the fourth preset time and the fifth preset time are different.

9. The in situ cleaning method of claim 1, wherein the fluorine containing cleaning gas comprises NF₃、CF₄、SF₆、C₂F₆、C₃F₈And one or more of argon and oxygen; the fluorine-containing cleaning gas comprises NF₃And argon, the NF₃The flow of the argon gas is 1000-10000 standard milliliters per minute, and the flow of the argon gas is 100-2000 standard milliliters per minute.

10. A PECVD device for a heterojunction solar cell comprises a reaction chamber, a radio frequency generator, a gas supply module for feeding a fluorine-containing cleaning gas to the reaction chamber, and a pressure adjusting module communicated with the reaction chamber for adjusting the pressure of the reaction chamber, the PECVD apparatus further comprises a cleaning controller for performing the in-situ cleaning method of any one of claims 1 to 9, the cleaning controller controls the gas supply module to introduce fluorine-containing cleaning gas into the reaction chamber, the cleaning controller controls the pressure regulating module to regulate the pressure of the reaction chamber to a first pressure, a second pressure, a third pressure, a fourth pressure, or a fifth pressure, and the cleaning controller controls to start the radio frequency generator and correspondingly lasts for a first preset time, a second preset time, a third preset time, a fourth preset time or a fifth preset time.

Technical Field

The invention relates to the field of PECVD (plasma enhanced chemical vapor deposition) equipment, in particular to an in-situ cleaning method for the PECVD equipment and corresponding PECVD equipment.

Background

Plasma Enhanced Chemical Vapor Deposition (PECVD) equipment is commonly used to deposit thin films on substrates such as semiconductor substrates, liquid crystal panels, and solar cells (high efficiency heterojunction solar cells). After the PECVD apparatus operates for a period of time, a silicon film (including intrinsic/doped silicon film polysilicon/amorphous silicon, etc.) layer with a predetermined thickness is deposited on the inner wall of the reaction chamber and the carrier plate in the chamber, and at this time, the PECVD apparatus is usually cleaned in situ without disassembly to remove the deposited silicon film layer.

Disclosure of Invention

In view of the above problems of the prior art, the present invention provides an in-situ cleaning method for a PECVD apparatus comprising a reaction chamber and a radio frequency generator, the method comprising the steps of: the method comprises the following steps that firstly, fluorine-containing cleaning gas is introduced into a reaction chamber, the pressure of the reaction chamber is adjusted to a first pressure, and a radio frequency generator is started and is kept for a first preset time; a second step of continuously introducing fluorine-containing cleaning gas into the reaction chamber, adjusting the pressure of the reaction chamber to a second pressure, and keeping the radio frequency generator continuously started for a second preset time; a third step of continuously introducing fluorine-containing cleaning gas into the reaction chamber, adjusting the pressure of the reaction chamber to a third pressure, and keeping the radio frequency generator continuously started for a third preset time; a fourth step of continuously introducing fluorine-containing cleaning gas into the reaction chamber, adjusting the pressure of the reaction chamber to a fourth pressure, and keeping the radio frequency generator continuously started for a fourth preset time; and a fifth step of continuously introducing fluorine-containing cleaning gas into the reaction chamber, adjusting the pressure of the reaction chamber to a fifth pressure, and keeping the radio frequency generator continuously started for a fifth preset time; wherein the first pressure, the second pressure, the third pressure, the fourth pressure and the fifth pressure are reduced from large to small in sequence.

In one embodiment, the first pressure is 0.55mbar to less than 0.65mbar, the second pressure is 0.45mbar to less than 0.55mbar, and the third pressure is 0.35mbar to less than 0.45 mbar; the fourth pressure is 0.25mbar to less than 0.35 mbar; the fifth pressure is 0.15mbar to less than 0.25 mbar.

In one embodiment, in the first to fifth steps, a fluorine-containing cleaning gas is ionized into a fluorine-containing plasma by the radio frequency generator, the fluorine-containing plasma reacts with a silicon film layer covering the inner wall of the reaction chamber and the surface of the carrier plate arranged in the reaction chamber, and the sum of the areas of the inner wall of the reaction chamber and the surface of the carrier plate is not less than 500mm × 500 mm.

In one embodiment, the silicon film layer includes intrinsic polysilicon, intrinsic amorphous silicon, phosphorus/boron doped polysilicon, phosphorus/boron doped amorphous silicon, a silicon carbon film, and a silicon oxide film.

In one embodiment, in the second step, the coverage area of the fluorine-containing plasma on the inner wall of the reaction chamber and the surface of the support plate after the first preset time and the second preset time is 60% to less than 70% of the total area of the inner wall of the reaction chamber and the surface of the support plate, and the flow rate of the fluorine-containing cleaning gas and the power of the radio frequency generator in the first step are correspondingly the same as those in the second step.

In an embodiment, in the third step, the coverage area of the fluorine-containing plasma on the inner wall of the reaction chamber and the surface of the support plate after the first preset time, the second preset time and the third preset time is 70% to less than 85% of the total area of the inner wall of the reaction chamber and the surface of the support plate, and the flow rate of the fluorine-containing cleaning gas and the power of the radio frequency generator in the second step are correspondingly the same as those in the third step.

In an embodiment, in the fourth step, the coverage area of the fluorine-containing plasma on the inner wall of the reaction chamber and the surface of the support plate after the first preset time, the second preset time, the third preset time and the fourth preset time is 85% to less than 100% of the total area of the inner wall of the reaction chamber and the surface of the support plate, and the flow rate of the fluorine-containing cleaning gas and the power of the radio frequency generator in the third step are correspondingly the same as or different from those in the fourth step.

In one embodiment, in the fifth step, the fluorine-containing plasma cleans the inner wall of the reaction chamber and the surface of the carrier plate with 100% total coverage, and the flow rate of the fluorine-containing cleaning gas and the power of the rf generator in the fourth step are the same or different from those in the fifth step.

In an embodiment, the first preset time, the second preset time, the third preset time, the fourth preset time and the fifth preset time are all the same, or at least two of the first preset time, the second preset time, the third preset time, the fourth preset time and the fifth preset time are different.

In one embodiment, the fluorine-containing cleaning gas comprises NF₃、CF₄、SF₆、C₂F₆、C₃F₈And one or more of argon and oxygen.

In one embodiment, the fluorine-containing cleaning gas comprises NF₃And argon, the NF₃The flow of the argon gas is 1000-10000 standard milliliters per minute, and the flow of the argon gas is 100-2000 standard milliliters per minute.

The invention also provides PECVD equipment for the heterojunction solar cell, which comprises a reaction chamber, a radio frequency generator, a gas supply module for feeding fluorine-containing cleaning gas to the reaction chamber, and a pressure regulating module communicated with the reaction chamber and used for regulating the pressure of the reaction chamber, the PECVD apparatus further comprises a cleaning controller for performing the in-situ cleaning method according to any of the embodiments described above, the cleaning controller controls the gas supply module to introduce fluorine-containing cleaning gas into the reaction chamber, the cleaning controller controls the pressure regulating module to regulate the pressure of the reaction chamber to a first pressure, a second pressure, a third pressure, a fourth pressure, or a fifth pressure, and the cleaning controller controls to start the radio frequency generator and correspondingly lasts for a first preset time, a second preset time, a third preset time, a fourth preset time or a fifth preset time.

Compared with the prior art that the plasma state reaching the surface to be cleaned is not considered as the influence factor of the cleaning efficiency, the in-situ cleaning method for the PECVD equipment divides the cleaning into five steps from the first step to the fifth step, wherein the pressure of the reaction chamber is reduced from high to low, fluorine-containing cleaning gas is introduced into the reaction chamber in each step, and the reverse cleaning gas is used for cleaning the surface to be cleanedThe chamber pressure is adjusted to a corresponding pressure and the rf generator is turned on for a corresponding time. The invention adopts the combined cleaning of the pressure intensity from large to small to the reaction chamber, so that the NF₃The ionization rate is maximized, and the coverage area of the fluorine-containing plasma is continuously increased, so that the cleaning efficiency of the large-area PECVD cavity wall and the silicon film layer on the support plate can be effectively improved, and the mass production process of the heterojunction solar cell can be effectively promoted.

Drawings

The above features and advantages of the present disclosure will be better understood upon reading the detailed description of embodiments of the disclosure in conjunction with the following drawings. In the drawings, components are not necessarily drawn to scale, and components having similar relative characteristics or features may have the same or similar reference numerals.

FIG. 1 is a schematic flow chart of an embodiment of an in-situ cleaning method for PECVD equipment.

FIG. 2 is a schematic diagram of the structure of a PECVD apparatus of the present invention.

Detailed description of the preferred embodiments

The invention will be described in detail below with reference to the accompanying drawings and specific embodiments so that the objects, features and advantages of the invention can be more clearly understood. It should be understood that the aspects described below in connection with the figures and the specific embodiments are exemplary only, and should not be construed as limiting the scope of the invention in any way. The singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise.

Referring to FIG. 1, a flow chart of an embodiment of a method 10 for in situ cleaning of PECVD apparatus of the present invention is shown. Referring collectively to fig. 2, the in situ cleaning method 10 of fig. 1 without opening the PECVD apparatus is adapted to: the inner walls (mainly the side walls and the top wall) 200 of the reaction chamber 20 of the PECVD apparatus 2 shown in fig. 2 and the silicon film layer disposed on the surface of the carrier plate 3 in the reaction chamber 20 reach a predetermined thickness corresponding to the thickness of the silicon film layer when the quality of the deposited silicon film layer in the PECVD apparatus will be affected if the silicon film layer is further thickened. The silicon film layer comprises intrinsic polycrystalline silicon, intrinsic amorphous silicon, phosphorus/boron doped polycrystalline silicon and phosphorus/boron doped amorphous siliconSilicon carbon film, silicon oxide film, and the like; wherein the intrinsic polycrystalline silicon and the intrinsic amorphous silicon are formed of Silane (SiH)₄) Deposited, phosphorus doped polysilicon/amorphous silicon is formed from Phosphane (PH)₃) And silane deposition, the boron doped polysilicon/amorphous silicon being formed from borane (B)₂H₆) And silane deposited, the silicon carbon film and the silicon oxygen film are formed by silane and carbon dioxide (CO)₂) Methane (CH)₄) And (4) deposition forming.

Referring to fig. 2, the PECVD apparatus may be a PECVD apparatus 2 for a heterojunction solar cell, the PECVD apparatus 2 including a reaction chamber 20, a radio frequency generator 21, a gas supply module 22, a gas exhaust line 23, a pressure regulating module 24, an upper electrode 25, a lower electrode 26, and a cleaning controller 27. The gas supply module 22 is used for feeding reaction gas or fluorine-containing cleaning gas to the reaction chamber 20, the exhaust pipeline 23 is used for exhausting gas in the reaction chamber 20, the pressure regulating module 24 is connected with the reaction chamber 20 and commonly used for regulating the pressure of the reaction chamber 20, the upper electrode 25 is electrically connected with the radio frequency generator 21, the lower electrode 26 is directly electrically connected with the ground, the pressure regulating module 24 can be communicated with the reaction chamber 20 through the exhaust pipeline 23, the carrier plate 3 is placed on the lower electrode 26, and the carrier plate 3 is provided with a plurality of bearing areas 30 for bearing silicon wafers.

The rf generator 21 (i.e., rf power supply) may employ a Capacitively Coupled (CCP) rf source or a high frequency source to plasmize the reactant gas or the fluorine-containing cleaning gas. The cleaning controller 27 is used for executing the in-situ cleaning method shown in fig. 1, and the cleaning controller 27 controls the gas supply module 22 to supply the fluorine-containing cleaning gas to the reaction chamber 20, controls the pressure regulating module 24 to regulate the pressure of the reaction chamber 20 to the corresponding cleaning pressure, and controls the rf generator 21 to be turned on for the corresponding preset time.

In the process of depositing the amorphous silicon thin film of the heterojunction solar cell by using the PECVD apparatus 2, a silicon film layer is formed on the inner wall 200 (mainly, the side wall and the top wall) of the reaction chamber 20 and the surface of the carrier plate 3 (excluding the silicon wafer carrying region 30) disposed in the reaction chamber 20, and when the silicon film layer reaches a predetermined thickness, the silicon film layer needs to be cleaned by using the in-situ cleaning method in fig. 1, that is, a cleaning gas is introduced to remove the silicon film layer.

With reference to fig. 1, the method 10 first performs step S100, introducing a fluorine-containing cleaning gas into a reaction chamber of a PECVD apparatus, adjusting the pressure of the reaction chamber to a first pressure, and starting a radio frequency generator of the PECVD apparatus for a first preset time.

The fluorine-containing cleaning gas comprises NF₃、CF₄、SF₆、C₂F₆、C₃F₈And one or more of argon and oxygen. In this embodiment, the fluorine-containing cleaning gas comprises NF₃And argon, the NF₃The flow rate of the argon is 1000-10000 standard milliliters per minute (sccm), and the flow rate of the argon is 100-2000 standard milliliters per minute (sccm); the first pressure is 0.55mbar to less than 0.65 mbar.

In step S100, the cleaning controller 27 controls the gas supply module 22 to supply the fluorine-containing cleaning gas into the reaction chamber 20, controls the pressure adjustment module 24 to adjust the pressure of the reaction chamber 20 to a first pressure, and controls the rf generator 21 to be turned on for a first preset time.

In step S100, a fluorine-containing cleaning gas is ionized into a fluorine-containing plasma by a radio frequency generator, the fluorine-containing plasma reacts with a silicon film layer covering the inner wall of the reaction chamber and the surface of the support plate disposed in the reaction chamber, and the sum of the areas of the inner wall of the reaction chamber and the surface of the support plate is not less than 500mm × 500 mm.

The method 10 then proceeds to step S110, where a fluorine-containing cleaning gas is continuously introduced into the reaction chamber, the pressure of the reaction chamber is adjusted to a second pressure, and the rf generator is kept on for a second preset time. The fluorine-containing plasma covers the inner wall of the reaction chamber and the surface of the support plate for 60% -less than 70% of the total area of the inner wall of the reaction chamber and the surface of the support plate after a first preset time and a second preset time (i.e. completing the steps S100 and S110), for example, 60% -68% or 60% -69% of the total area of the inner wall of the reaction chamber and the surface of the support plate, and then 60% -less than 70% of the total area of the inner wall of the reaction chamber and the surface of the support plate can be cleaned, wherein the flow rate of the fluorine-containing cleaning gas and the power of the radio frequency generator in the step S100 are correspondingly. In this embodiment, the second pressure is 0.45mbar to less than 0.55 mbar.

In step S110, the cleaning controller 27 controls the gas supply module 22 to supply the fluorine-containing cleaning gas into the reaction chamber 20, controls the pressure adjustment module 24 to adjust the pressure of the reaction chamber 20 to a second pressure, and controls the rf generator 21 to be turned on for a second preset time, so as to clean the silicon film layer covering a region of 60% to less than 70% (e.g. 68% or 69%) of the total area of the inner wall of the reaction chamber and the surface of the carrier plate.

The method 10 then proceeds to step S120, where a fluorine-containing cleaning gas is continuously introduced into the reaction chamber, the pressure of the reaction chamber is adjusted to a third pressure, and the radio frequency generator is kept on for a third preset time. In this embodiment, the third pressure is 0.35mbar to less than 0.45 mbar. In step S120, the coverage area of the fluorine-containing plasma on the inner wall of the reaction chamber and the surface of the support plate after the first preset time, the second preset time and the third preset time (i.e. completing steps S100, S110 and S120) reaches 70% to less than 85% of the total area of the two, for example, 70% to 83% or 70% to 84% of the total area of the two, and the flow rate of the fluorine-containing cleaning gas and the power of the rf generator in step S110 are the same as or different from those in step S120.

In step S120, the cleaning controller 27 controls the gas supply module 22 to introduce the fluorine-containing cleaning gas into the reaction chamber 20, controls the pressure adjustment module 24 to adjust the pressure of the reaction chamber 20 to a third pressure, and controls the rf generator 21 to be turned on for a third preset time, so as to clean the silicon film layer covering a region of 70% to less than 85% (e.g., 83% or 84%) of the total area of the inner wall of the reaction chamber and the surface of the support plate.

The method 10 then proceeds to step S130, where a fluorine-containing cleaning gas is continuously introduced into the reaction chamber, the pressure of the reaction chamber is adjusted to a fourth pressure, and the radio frequency generator is kept on for a fourth preset time. In step S130, the coverage area of the fluorine-containing plasma on the inner wall of the reaction chamber and the surface of the support plate after the first preset time, the second preset time, the third preset time and the fourth preset time (i.e. completing steps S100, S110, S120 and S130) reaches 85% to less than 100% of the total area of the two, for example, 85% to 98% or 85% to 99% of the total area of the two, and the flow rate of the fluorine-containing cleaning gas and the power of the rf generator in step S120 may be the same as or different from the flow rate of the fluorine-containing cleaning gas and the power of the rf generator in step S130. In this embodiment, the fourth pressure is 0.25mbar to less than 0.35 mbar.

In step S130, the cleaning controller 27 controls the gas supply module 22 to introduce the fluorine-containing cleaning gas into the reaction chamber 20, controls the pressure adjustment module 24 to adjust the pressure of the reaction chamber 20 to a fourth pressure, and controls the rf generator 21 to be turned on for a fourth preset time, so as to clean the silicon film layer covering a region between 85% and less than 100% (e.g., 98% or 99%) of the total area of the inner wall of the reaction chamber and the surface of the carrier plate.

The method 10 then proceeds to step S140, where a fluorine-containing cleaning gas is continuously introduced into the reaction chamber, the pressure of the reaction chamber is adjusted to a fifth pressure, and the rf generator is kept on for a fifth preset time. In step S140, the fluorine-containing plasma cleans the inner wall of the reaction chamber and the surface of the carrier plate with 100% total coverage, and the flow rate of the fluorine-containing cleaning gas and the power of the rf generator in step S130 are the same or different from those in step S140. In this embodiment, the fifth pressure is 0.15mbar to less than 0.25 mbar.

In step S140, the cleaning controller 27 controls the gas supply module 22 to introduce the fluorine-containing cleaning gas into the reaction chamber 20, controls the pressure adjustment module 24 to adjust the pressure of the reaction chamber 20 to a fifth pressure, and controls the rf generator 21 to be turned on for a fifth preset time, so as to clean the silicon film layer covering the entire area of 100% of the total area of the inner wall of the reaction chamber and the surface of the carrier plate.

The first pressure, the second pressure, the third pressure, the fourth pressure and the fifth pressure in the above steps S100 to S140 decrease from large to small in order. The first preset time, the second preset time, the third preset time, the fourth preset time and the fifth preset time in the steps S100 to S140 may all be the same, or at least two of the first preset time, the second preset time, the third preset time, the fourth preset time and the fifth preset time may be different, and the five times may be different from each other and may be adjusted according to an actual cleaning effect.

The cleaning method for the PECVD equipment comprises the steps of dividing the cleaning into five steps from the first step to the fifth step, wherein the pressure of a reaction chamber is reduced from high to low in sequence, introducing fluorine-containing cleaning gas into the reaction chamber in each step, adjusting the pressure of the reaction chamber to the corresponding pressure, and starting a radio frequency generator for corresponding time. The invention adopts the combined cleaning of the pressure intensity from large to small to the reaction chamber, so that the NF₃The ionization rate is maximized, and the coverage area of the fluorine-containing plasma is continuously increased, so that the cleaning efficiency of the large-area PECVD cavity wall and the silicon film layer on the support plate can be effectively improved, and the mass production process of the heterojunction solar cell can be effectively promoted.

The embodiments described above are provided to enable persons skilled in the art to make or use the invention and that modifications or variations can be made to the embodiments described above by persons skilled in the art without departing from the inventive concept of the present invention, so that the scope of protection of the present invention is not limited by the embodiments described above but should be accorded the widest scope consistent with the innovative features set forth in the claims.