Graphite boat cleaning method, control device and cleaning equipment

Abstract

The invention provides a graphite boat cleaning method, a control device and cleaning equipment, and relates to the technical field of plasma cleaning, the graphite boat cleaning method can be applied to graphite boat dry cleaning, and a first electrode and a second electrode arranged opposite to the first electrode are arranged on the inner wall of a closed cavity; the first electrode and the second electrode are connected to two electrodes of the same power source; controlling a power source to excite a gas substance introduced into the closed cavity through an electric field generated by the first electrode and the second electrode to generate plasma, wherein the plasma cleans a graphite boat placed between the first electrode and the second electrode; the power source is an alternating current signal. The double electrodes are driven by the alternating-current power supply to alternately excite the plasma, the ions are guided by the periodically changing electric field to reciprocate and cover the complex structure on the surface of the graphite boat, meanwhile, electrode polarization loss is avoided, the cleaning efficiency can be effectively improved, electrode loss is reduced, local overheating is avoided, and plasma uniform distribution is achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of plasma cleaning, in particular to a graphite boat cleaning method, control device and cleaning equipment. BACKGROUND

[0002] In the photovoltaic manufacturing industry, graphite boats, as key process tools for carrying photovoltaic panels, are widely used in high-temperature process links such as chemical vapor deposition and diffusion furnaces, for fixing and transporting wafers or substrates. Due to the effects of high-temperature environment and active gas in the process, silicon nitride and other refractory deposits and by-products will continuously accumulate on the surface of the graphite boat. These contaminants not only reduce the uniformity of subsequent processes, but also can cause serious problems such as photovoltaic panel contamination and device performance degradation, so the surface cleanliness of the graphite boat must be maintained through regular cleaning.

[0003] The existing technology mainly uses direct current or radio frequency power sources to excite plasma to achieve dry cleaning of graphite boats, but the existing equipment is difficult to maintain stable plasma density, resulting in large fluctuations in cleaning efficiency, incomplete cleaning in dead angle areas and other problems. SUMMARY

[0004] The main purpose of the present application is to provide a graphite boat cleaning method to improve cleaning efficiency.

[0005] To achieve the above purpose, the present application provides a graphite boat cleaning method which can be applied to dry cleaning of graphite boats: A first electrode is arranged on the inner wall of the closed chamber, and a second electrode is arranged opposite the first electrode, the first electrode and the second electrode are connected to two poles of the same power source; The power source is controlled to generate an electric field through the first electrode and the second electrode to excite the gas material introduced into the closed chamber to generate plasma, and the plasma cleans the graphite boat placed between the first electrode and the second electrode; the power source is an alternating signal.

[0006] Optionally, the power source is controlled to generate an electric field through the first electrode and the second electrode to excite the gas material introduced into the closed chamber to generate plasma, and the plasma cleans the graphite boat placed between the first electrode and the second electrode, comprising: A first operating frequency of the power source is obtained, and a first transformation time corresponding to the first operating frequency is determined; The power source is controlled to generate an electric field in a first direction through the first electrode and the second electrode, so that the charged ions and groups used for cleaning in the plasma move along the first direction; in the case that the first power source conversion time reaches a threshold, control the power source to convert the polarity of the power source, so that the first electrode and the second electrode generate an electric field in a second direction, and the positively charged ions or radicals in the plasma move in the second direction, the first direction and the second direction being opposite directions; According to the first power source conversion time, the polarity of the power source output by the power source is converted, so that the positively charged ions or radicals in the plasma move in the first direction and the second direction.

[0007] Optionally, the power source includes an ignition direct current source; The control of the power source by the first electrode and the second electrode generates an electric field to excite the gas material in the sealed chamber to generate plasma, specifically: Determine the zero position of the first conversion time; In the case that each first conversion time is at the zero position, control the ignition direct current source to access the first electrode and the second electrode to control the gas material in the sealed chamber to generate plasma.

[0008] Optionally, the control of the power source by the first electrode and the second electrode generates an electric field to excite the gas material in the sealed chamber to generate plasma, and the plasma cleans the graphite boat placed between the first electrode and the second electrode, comprising: Obtain the second operating frequency corresponding to a plurality of cleaning stages of the power source, determine the second conversion time corresponding to the second operating frequency, and arrange the second operating frequency corresponding to a plurality of cleaning stages in descending order according to time; According to the second power source conversion time, the positive and negative voltages applied to the first electrode and the second electrode are converted, so that the charged ions and radicals used for cleaning in the plasma move along the direction of the electric field.

[0009] Optionally, the cleaning method of the graphite boat further comprises: Obtain the first plasma concentration distribution data of the sealed chamber, and determine the aggregation position of the plasma; Determine the first distance between the aggregation position and the first electrode, and the second distance between the aggregation position and the second electrode; According to the size relationship between the first distance and the second distance, adjust the polarity of the power source output by the first electrode and the second electrode, so that the first distance and the second distance gradually tend to be equal.

[0010] Optionally, the cleaning method of the graphite boat further comprises: Obtain the current second plasma concentration distribution data of the sealed chamber; determining an optimal cleaning path corresponding to the plasma concentration distribution data; adjusting a first current outputted by the first electrode and a second current outputted by the second electrode according to the optimal cleaning path, so as to drive the plasma to move on the surface of the graphite boat along a direction of an electric field corresponding to the optimal cleaning path.

[0011] Optionally, the sealed chamber comprises a transfer chamber and a cleaning chamber, and a passage door is arranged between the transfer chamber and the cleaning chamber. The method for cleaning the graphite boat further comprises: before the cleaning is performed, the transfer chamber is opened, and the graphite boat to be cleaned is sent into the transfer chamber; after the transfer chamber is vacuumized, the passage door between the transfer chamber and the cleaning chamber is opened, so as to control the graphite boat to be cleaned to be transferred from the transfer chamber to the cleaning chamber for cleaning.

[0012] Optionally, the method for cleaning the graphite boat further comprises: acquiring current temperature data and pressure data of the sealed chamber; determining first cleaning parameters corresponding to the temperature data and the pressure data; determining a frequency conversion of the power source according to the first cleaning parameters, so as to adjust a moving speed of the plasma on the surface of the graphite boat; The method for cleaning the graphite boat further comprises: in response to second cleaning parameters inputted by a user, acquiring a frequency deviation value of a frequency in the second cleaning parameters from a current frequency of the power source; correcting the current frequency of the power source according to the frequency deviation value, so as to adjust the moving speed of the plasma on the surface of the graphite boat.

[0013] In addition, to achieve the above-mentioned purposes, the present application further provides a control device, which comprises a memory, a processor, and a graphite boat cleaning program stored in the memory and executable on the processor, and the graphite boat cleaning program is configured to implement the above-mentioned method for cleaning the graphite boat.

[0014] In addition, to achieve the above-mentioned purposes, the present application further provides a graphite boat cleaning device, which comprises the above-mentioned control device, and the graphite boat cleaning device is used for dry cleaning of the graphite boat.

[0015] The embodiment of the present application is characterized in that a first electrode is arranged on the inner wall of the closed chamber, a second electrode is arranged opposite to the first electrode, the first electrode and the second electrode are connected to two poles of the same power source, and the power source is controlled to generate an electric field through the first electrode and the second electrode to excite the gas material in the closed chamber to generate plasma, and the plasma is used to clean the graphite boat placed between the first electrode and the second electrode, wherein the power source is an alternating current signal. In this way, the alternating current power source is used to drive the double electrodes to alternately excite the plasma, the periodically changed electric field is used to guide the ions to reciprocate, the surface of the graphite boat with complex structure is covered, the electrode polarization loss is avoided, the cleaning efficiency is effectively improved, the electrode loss is reduced, the local overheating is avoided, and the uniform distribution of the plasma is realized. BRIEF DESCRIPTION OF DRAWINGS

[0016] The drawings incorporated in the specification and constituting a part thereof illustrate embodiments consistent with the present application and together with the specification are used to explain the principles of the application.

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0018] Figure 1 The flowchart of the cleaning method of the graphite boat according to an embodiment of the present application is shown in the figure. Figure 2 The flowchart of the cleaning method of the graphite boat according to another embodiment of the present application is shown in the figure. Figure 3 The flowchart of the cleaning method of the graphite boat according to another embodiment of the present application is shown in the figure. Figure 4 The flowchart of the cleaning method of the graphite boat according to another embodiment of the present application is shown in the figure. Figure 5 The flowchart of the cleaning method of the graphite boat according to another embodiment of the present application is shown in the figure. Figure 6 The flowchart of the cleaning method of the graphite boat according to another embodiment of the present application is shown in the figure. Figure 7 The flowchart of the cleaning method of the graphite boat according to another embodiment of the present application is shown in the figure. Figure 8 The flowchart of the cleaning method of the graphite boat according to another embodiment of the present application is shown in the figure. Figure 9 The flowchart of the cleaning method of the graphite boat according to another embodiment of the present application is shown in the figure. Figure 10A voltage waveform diagram for the operation of the power source.

[0019] The implementation, functional features and advantages of the present application will be further described with reference to the embodiments in combination with the accompanying drawings. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. The well-known modules, units and connections, links, communications or operations therebetween are not shown or not described in detail. And the described features, architectures or functions can be combined in any way in one or more embodiments. It should be understood by those skilled in the art that the following various embodiments are only used for illustration, and are not used to limit the protection scope of the present application. It can also be easily understood that the modules or units or processing manners in each embodiment described herein and shown in the drawings can be combined and designed in various different configurations. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0021] In the following embodiments, the definition of various nouns or methods is generally based on the broad concept that can be implemented on the premise of the disclosed content in the embodiments, except for the cases that are logically impossible. Under such understanding, various specific lower specific definitions of the nouns or methods should be regarded as the invention content of the present application, and should not be regarded as the specific definition not disclosed in the specification, and should not be understood or interpreted in a biased manner. Similarly, under the premise that the order of steps in the method can be logically implemented, the specific lower specific definition of the broad concept of various nouns or methods falls within the protection scope of the present application.

[0022] In the semiconductor and photovoltaic manufacturing industry, graphite boats are widely used as key process carrying tools in high-temperature process links such as chemical vapor deposition and diffusion furnaces, for fixing and transporting wafers or substrates. Due to the action of high-temperature environment and active gas in the process, silicon nitride and other refractory deposits and by-products will continue to accumulate on the surface of the graphite boat. These contaminants not only reduce the uniformity of subsequent processes, but also may cause wafer contamination, device performance degradation and other serious problems, so the surface cleanliness of the graphite boat must be maintained by regular cleaning.

[0023] Traditional cleaning mainly adopts wet process, i.e. through strong corrosive chemical reagents such as hydrofluoric acid and nitric acid for soaking and flushing. Although this method can remove part of the pollutants, it has significant defects: first, the treatment cost of strong acid waste liquid is high and easy to cause environmental pollution; second, chemical residues may penetrate into the graphite micropores to cause secondary pollution; in addition, repeated acid washing will erode the graphite structure, significantly shorten the service life of the boat. More seriously, for chemically inert substances such as silicon nitride, wet cleaning often needs to be combined with mechanical grinding, which may damage the precise structure of the graphite boat.

[0024] In order to break through the limitations of wet process, dry plasma cleaning technology has been gradually applied. The existing technology mainly uses direct current or radio frequency power supply to excite plasma, but has the following inherent defects: direct current plasma is easy to cause electrode polarization loss, and the radio frequency system is expensive and complex to control; both methods have the problem of uneven distribution of plasma, which is difficult to cover the complex groove structure of the graphite boat; in addition, directional bombardment of ions may cause local overheating and damage to the surface of the graphite boat. Especially when processing large-size graphite boats, the existing equipment is difficult to maintain stable plasma density, resulting in large fluctuations in cleaning efficiency, incomplete cleaning of dead angle areas and other problems.

[0025] The main solution of the embodiment of the present application is: a first electrode is arranged on the inner wall of the closed chamber, and a second electrode is arranged opposite to the first electrode, the first electrode and the second electrode are connected to two poles of the same power source, and the power source is controlled to excite the gas material introduced into the closed chamber to generate plasma through the first electrode and the second electrode, and the plasma cleans the graphite boat placed between the first electrode and the second electrode, wherein the power source is an alternating current signal.

[0026] In the embodiment, for convenience of description, the following describes the control device as the main body of execution.

[0027] The present application provides a solution, which drives the double electrodes to alternately excite plasma by alternating current power supply, uses the periodically transformed electric field to guide the reciprocating motion of ions, covers the complex structure of the surface of the graphite boat, avoids electrode polarization loss, and can effectively improve the cleaning efficiency, reduce electrode loss, avoid local overheating and realize uniform distribution of plasma.

[0028] To this end, the application provides a graphite boat cleaning method; it can be understood that the graphite boat cleaning device is provided with a control device for storing and executing the following method, and the control device can be realized by a main controller, such as MCU (Micro controller Unit), DSP (Digital Signal Process), FPGA (Field Programmable Gate Array), SOC (System On Chip) and the like.

[0029] In the prior art, the semiconductor and photovoltaic manufacturing industry relies on graphite boats as a bearing tool for high-temperature processes, and the surface residues thereof need to be cleaned regularly to ensure process quality. The traditional wet cleaning uses strong acid and strong base, which has problems of environmental pollution, chemical residue and equipment corrosion. The existing dry cleaning uses direct current or radio frequency power supply to excite plasma, but has defects of uneven distribution, electrode loss and unstable cleaning efficiency, and the complex structure graphite boat is prone to local incomplete cleaning or overheating damage.

[0030] In order to solve the above problems, it is necessary to design a cleaning scheme capable of stably exciting uniform plasma and reducing equipment loss. Through analysis, it is found that the direct current power supply is easy to cause unilateral loss of the electrode, and the radio frequency power supply device is complex and has high maintenance cost. If an alternating current power supply is used in cooperation with a symmetrical electrode structure, the direction of the electric field can be periodically switched to promote uniform motion of ions, and the loss of the electrode can be balanced. Considering the gas excitation efficiency of the sealed chamber, the double-electrode opposite layout can form a stable electric field coverage area to ensure that the plasma fully acts on the surface of the graphite boat.

[0031] Based on the above content, with reference to Figure 1 In an embodiment of the application, the graphite boat cleaning method can be applied to graphite boat dry cleaning, such as tube PECVD (abbreviated as tube P), and the graphite boat cleaning method comprises steps S100-S200, wherein: S100, a first electrode is arranged on the inner wall of the sealed chamber, and a second electrode is arranged opposite to the first electrode, and the first electrode and the second electrode are connected to two poles of the same power source; S200, the power source is controlled to generate an electric field through the first electrode and the second electrode to excite gas material introduced into the sealed chamber to generate plasma, and the plasma cleans the graphite boat placed between the first electrode and the second electrode; the power source is an alternating current signal.

[0032] The closed chamber refers to a sealed container capable of maintaining a vacuum or a specific gas environment, which can be realized by using stainless steel or quartz material in combination with a vacuum pump system, for isolating the external environment and bearing the cleaning process. The first electrode and the second electrode refer to conductive bodies distributed in parallel or symmetrically, which can be made of graphite or metal, and the distance between the two can be adjusted to adapt to graphite boats of different sizes, forming a uniform electric field covering the area to be cleaned. The alternating current power source refers to a device that outputs an electric signal with periodically changing polarity, which can be a sine wave or square wave generator. By adjusting the frequency to control the switching period of ion movement direction, the positive charged particles are promoted to reciprocally impact on the surface of the graphite boat.

[0033] During the cleaning process, the graphite boat is placed between the two electrodes, and inert or reactive gas is introduced into the chamber. After the alternating current power source is started, an alternating electric field is formed between the electrodes, and gas molecules are ionized to form plasma. The positively charged ions are attracted to the second electrode by the positive voltage of the first electrode during the positive half cycle of the electric field, and impact on the surface of the graphite boat to clean the silicon nitride attached to the surface of the graphite boat. During the negative half cycle, the direction of the electric field is reversed, and the direction of ion movement is also changed. Periodic direction switching causes the ions to form a bidirectional flushing on the surface of the graphite boat, avoiding dead angles caused by one-way motion, while the alternating polarity of the electrodes balances the charge accumulation, prolonging the service life of the electrodes.

[0034] In this embodiment, the microscopic mechanism involves positively charged cations or groups moving under the action of the electric field formed by the first electrode and the second electrode. These positively charged particles or groups move in the direction of opposite charges driven by the electric field force, generating kinetic energy. When these positively charged particles or groups impact the surface of the graphite boat at a certain speed and energy, they physically impact and hit the silicon nitride particles attached to the surface of the graphite boat. Through this physical impact and hit, the silicon nitride particles are stripped and removed, achieving the cleaning effect of the surface of the graphite boat. The whole process is carried out under the action of the electric field, and the existence of the electric field enables the positively charged particles or groups to effectively move and impact the target, achieving the purpose of cleaning.

[0035] Compared with the prior art, the direct current power source cleaning causes the ions to move in one direction due to the fixed direction of the electric field, which is easy to form a shadow effect on the surface of complex structures, and the radio frequency power source requires an impedance matching network to increase the complexity of the equipment. The alternating current power source directly drives the symmetric electrodes in this embodiment, which not only eliminates the limitation of one-way motion, but also simplifies the structure of the power supply system. The double-electrode opposite layout can form a more uniform electric field distribution compared with single-electrode or asymmetric layout, and cooperate with the periodic reversal of the alternating current signal to achieve dynamic balance of the plasma concentration and avoid local overheating.

[0036] Through the technical solution, the graphite boat surface attachment is cleaned by bidirectional physical bombardment, complex structure surface recessed areas are effectively covered, electrode loss is uniformly distributed under the action of alternating current field, equipment maintenance cycle is prolonged, chemical pollution is reduced by the closed chamber and gas circulation system, and environmental protection production requirements are met.

[0037] In the embodiment, the first electrode and the second electrode are connected to two poles of the same power source, and the power source is controlled to excite gas material introduced into the closed chamber to generate plasma through the first electrode and the second electrode, and the plasma cleans the graphite boat placed between the first electrode and the second electrode, wherein the power source is an alternating current signal. In this way, the alternating current power source drives the double electrodes to alternately excite the plasma, the periodically changed electric field guides the ions to reciprocate, covers the complex structure on the surface of the graphite boat, avoids electrode polarization loss, effectively improves the cleaning efficiency, reduces the electrode loss, avoids local overheating, and realizes uniform distribution of the plasma.

[0038] Optionally, referring to Figure 2 Another embodiment of the present application provides a graphite boat cleaning method based on the above Figure 1 The power source is controlled to excite gas material introduced into the closed chamber to generate plasma through the first electrode and the second electrode, and the plasma cleans the graphite boat placed between the first electrode and the second electrode, including steps S210-S240, wherein: S210, a first operating frequency of the power source is obtained, and a first transformation time corresponding to the first operating frequency is determined; S220, the power source is controlled to generate an electric field in a first direction through the first electrode and the second electrode, so that charged ions and groups in the plasma for cleaning move along the first direction; S230, in the case that the first power source transformation time reaches a threshold value, the power source is controlled to change the power supply polarity, so that the first electrode and the second electrode generate an electric field in a second direction, so that positively charged ions or groups in the plasma move along the second direction, and the first direction and the second direction are opposite directions; S240, the power supply polarity output by the power source is changed according to the first power source transformation time, so that the positively charged ions or groups in the plasma move along the first direction and the second direction Wherein, the first operating frequency refers to the frequency of the alternating current signal output by the power source, which can be adjusted by a programmable frequency generator, and its value is directly related to the electrode polarity switching speed. The first switching time refers to the time interval of electrode polarity switching, which can be realized by a timing module or a pulse counter, and its value is inversely proportional to the operating frequency. The first switching time is used to ensure that the ions complete directional migration in a specific area before switching the direction of motion. The threshold value refers to the condition parameter for triggering electrode polarity switching, which can be set as a fixed time value or a dynamically calculated value, and is used to prevent premature polarity switching from causing incomplete ion motion path.

[0039] Wherein, after the reaction gas is introduced into the closed chamber, the power source outputs an alternating current signal at a preset frequency to drive the first electrode and the second electrode. By monitoring the operating frequency of the power source in real time, the corresponding electrode polarity switching time interval is calculated. When the power source generates an electric field from the first electrode to the second electrode, i.e. an electric field in the first direction, through the first electrode and the second electrode, the positively charged ions move in the direction of the second electrode under the action of the electric field and hit the surface of the graphite boat along the direction of the electric field; when the preset time threshold is reached, the polarity of the power source of the first electrode and the second electrode is reversed, and the motion direction of the positively charged ions and / or groups is changed, i.e. from the second electrode to the first electrode. By periodically switching the polarity of the electrodes, the ions form a reciprocating scouring path on the surface of the graphite boat, covering different areas of the adherends.

[0040] The prior art plasma cleaning equipment usually uses a fixed frequency alternating current power source or a unidirectional direct current electric field, resulting in a single direction of ion motion, which is easy to form a cleaning dead angle on the surface of the graphite boat. The embodiment dynamically matches the frequency and the polarity switching time, so that the ions form a bidirectional motion path under the action of the alternating electric field, effectively expanding the cleaning coverage.

[0041] The embodiment can eliminate the phenomenon of local cleaning unevenness on the surface of the graphite boat caused by single-direction ion motion, avoid the accumulation of silicon nitride residues in a specific area, and improve the overall cleaning efficiency. At the same time, by periodically switching the direction of the electric field, the material loss caused by long-term single-pole work on the surface of the electrode can be reduced, and the service life of the equipment can be prolonged.

[0042] Optionally, referring to Figure 3 and Figure 10 , another embodiment of the present application provides a cleaning method for a graphite boat, based on the above Figure 2 indicated embodiment, the power source includes an ignition direct current source; the power source generates an electric field through the first electrode and the second electrode to excite the gas material introduced into the closed chamber to generate plasma, specifically steps S250-S260, wherein: S250, determine the zero point position of the first switching time; S260, in the case that the first switching time is at the zero point position, controlling the ignition DC source to access the first electrode and the second electrode to control the gas substance in the closed chamber to generate plasma.

[0043] Wherein, the ignition DC source refers to a DC power supply outputting constant polarity voltage, which functions to provide a short energy pulse near the zero point of the AC signal to assist in exciting gas molecules to ionize. Unlike the continuous AC signal, the ignition DC source only accesses at a specific moment, and the duration is extremely short, usually several microseconds to tens of microseconds, to avoid interference with the AC electric field. By precisely controlling the access time and duration of the ignition DC source, the generation efficiency and stability of the plasma can be effectively enhanced without affecting the regularity of ion movement. The zero point position refers to the exact correspondence point of the power source output waveform and the electrode polarity switching moment, i.e. the zero crossing point in the AC signal cycle. In the sinusoidal waveform of the AC signal, the zero point position appears at the moment of transition from positive to negative or from negative to positive, at which time the voltage value is zero and the electric field strength is zero, and the ions are in a temporary stationary state. By precisely capturing these zero point positions, the ignition DC source can be briefly accessed to provide additional ionization energy for gas molecules before the electric field direction is about to change, promoting stable generation of plasma.

[0044] Wherein, since a high voltage is initially required to excite plasma for electrode direction switching, the present embodiment calculates the zero point position in each AC cycle by monitoring the operating frequency and switching time of the power source. When the first switching time reaches the zero point position, the ignition DC source is briefly accessed between the first electrode and the second electrode to provide additional ionization energy for the gas molecules in the closed chamber. This process is completed before the direction of the AC electric field is about to switch, so it will not affect the direction of ion movement. Through the auxiliary excitation of the ignition DC source, it can be ensured that plasma is stably generated in each AC cycle, improving the continuity and stability of the cleaning process.

[0045] Compared with the prior art, the present embodiment realizes stable and efficient excitation of plasma by introducing the ignition DC source and precisely controlling the zero point position of the AC signal. This method not only improves the cleaning efficiency, but also reduces the wear of the electrodes and prolongs the service life of the equipment. In addition, since the ignition DC source only accesses at a specific moment, it will not significantly affect the overall energy consumption.

[0046] Optionally, referring to Figure 4 , a further embodiment of the present application provides a cleaning method for a graphite boat based on the above Figure 1In the illustrated embodiment, the power source is controlled to generate an electric field between the first electrode and the second electrode to excite a gas material in the sealed chamber to generate a plasma, and the plasma is used to clean a graphite boat placed between the first electrode and the second electrode, including steps S270-S280, wherein: S270, obtaining a second operating frequency corresponding to each cleaning stage of the power source, determining a second conversion time corresponding to the second operating frequency, and arranging the second operating frequency corresponding to each cleaning stage in a descending order according to time; S280, converting the positive and negative voltages applied to the first electrode and the second electrode according to the second power conversion time, so that the positively charged ions or groups in the plasma move along the direction of the electric field.

[0047] The second operating frequency corresponding to each cleaning stage refers to that the total time length is divided into several time periods during the cleaning process, and the frequency of the alternating current signal output by the power source is set to different values in each time period. The frequency parameter can be adjusted dynamically by using a preset program or a sensor feedback. The frequency value gradually decreases over time. The second conversion time refers to the time interval of the electrode polarity switching in each cleaning stage, which can be calculated by the inverse relationship between frequency and time. For example, when the frequency decreases, the conversion time is correspondingly extended. Arranging the second operating frequency in a descending order according to time refers to that the second operating frequency is set to a higher value in the initial stage, and then decreases in the subsequent stages. The frequency can be adjusted in a stepwise or continuous gradual manner.

[0048] In the initial stage of cleaning, the power source is set to a higher frequency, and at this time, the electrode polarity switching interval is shorter, and the positively charged ions or groups move back and forth quickly under the action of the electric field to impact the surface of the graphite boat at a high frequency to remove large particle contaminants. As the cleaning stage progresses, the operating frequency gradually decreases, and the conversion time gradually extends, and the movement speed of the ions or groups slows down, but the action time increases, so that the fine residues are physically impacted more deeply. By adjusting the frequency in stages, the main contaminants can be efficiently removed in the initial stage, and the graphite boat surface can be prevented from being damaged due to excessive energy in the later stage, while ensuring that contaminants of different depths are peeled off layer by layer.

[0049] The existing plasma cleaning usually adopts fixed frequency or single-stage adjustment, which leads to uneven energy distribution during the cleaning process, and easy formation of excessive cleaning or insufficient cleaning in local areas. The embodiment of the present application matches the plasma energy distribution with the pollution level by using a multi-stage frequency decreasing design, dynamically adapts to different cleaning requirements, improves the overall cleaning efficiency, and avoids equipment damage caused by energy concentration.

[0050] The embodiment can automatically adjust the cleaning intensity according to the type and attachment degree of the pollutants, reduce the physical impact on the surface of the graphite boat while ensuring the cleaning effect, realize a more uniform and controllable dry cleaning process, and effectively solve the problem of incomplete removal of residues on the surface of a complex structure.

[0051] Optionally, with reference to Figure 5 , the present application also provides a graphite boat cleaning method based on the above Figure 1 The graphite boat cleaning method shown in the embodiment further comprises steps S300-S500, wherein: S300, acquiring first plasma concentration distribution data of the sealed chamber to determine the aggregation position of the plasma; S400, determining a first distance between the aggregation position and the first electrode, and a second distance between the aggregation position and the second electrode; S500, adjusting the power supply polarity output by the first electrode and the second electrode according to the size relationship between the first distance and the second distance, so that the first distance and the second distance gradually tend to be equal.

[0052] The first plasma concentration distribution data refers to data obtained by real-time monitoring of the plasma concentration in different regions of the sealed chamber by a plasma concentration sensor or detection device, which can be realized by an optical emission spectrometer or a probe array. The first plasma concentration distribution data is used to identify the aggregation area of the plasma in the chamber. The aggregation position refers to a local position where the plasma concentration is significantly higher than that in other regions, which can be determined by concentration gradient analysis or image recognition algorithm. The aggregation position may be formed due to uneven electric field distribution or abnormal gas flow. The first distance and the second distance refer to the physical distance from the aggregation position to the first electrode and the second electrode, respectively, which can be measured by laser ranging or coordinate mapping technology. The first distance and the second distance are used to quantify the relative position relationship between the electrodes and the plasma aggregation area. Adjusting the power supply polarity refers to changing the voltage polarity distribution between the first electrode and the second electrode, which can be realized by switching the phase of the alternating current power supply or using a bidirectional switch circuit, so as to change the electric field direction to affect the plasma distribution.

[0053] Wherein, during the cleaning process, the plasma concentration distribution data in the closed chamber is collected in real time, and the polymerization position with abnormally high plasma concentration is analyzed. Subsequently, the distance between the polymerization position and the two electrodes is calculated respectively. If the first distance is significantly greater than the second distance, it indicates that the plasma is closer to the second electrode. At this time, the first electrode is changed to negative voltage and the second electrode is changed to positive voltage by switching the power polarity, so as to adjust the direction of the electric field and promote the plasma to migrate towards the first electrode. Conversely, if the second distance is greater, the first electrode is changed to positive voltage and the second electrode is changed to negative voltage. By repeatedly adjusting the power polarity, the polymerization position gradually moves to the middle of the two electrodes, and finally the dynamic balance of the first distance and the second distance is realized, ensuring the uniform distribution of the plasma in the chamber.

[0054] The prior art plasma cleaning equipment usually adopts fixed electrode polarity or single frequency alternating current power supply, which causes the plasma to easily gather near a certain electrode, causing uneven cleaning or local overheating problems. However, the embodiment can actively correct the deviation trend of the plasma by real-time monitoring of the plasma distribution and dynamically adjusting the electrode polarity, thereby avoiding the concentration imbalance caused by asymmetric electric field.

[0055] The embodiment can effectively eliminate the local aggregation of the plasma in the closed chamber, improve the cleaning uniformity, and reduce the cleaning dead angle or excessive etching problem caused by uneven concentration distribution. At the same time, the dynamic adjustment of the electrode polarity can prolong the service life of the electrode and avoid the electrode material loss caused by long-term unidirectional electric field effect.

[0056] Optionally, referring to Figure 6 Another embodiment of the present application provides a cleaning method for a graphite boat, based on the above Figure 1 The cleaning method for the graphite boat further comprises steps S600-S800, wherein: S600, acquiring current second plasma concentration distribution data of the closed chamber; S700, determining an optimal cleaning path corresponding to the plasma concentration distribution data; S800, adjusting the first current output by the first electrode and the second current output by the second electrode according to the optimal cleaning path, so as to drive the plasma to move on the surface of the graphite boat along the direction of the electric field corresponding to the optimal cleaning path.

[0057] The second plasma concentration distribution data refers to the plasma density information of different regions in the sealed chamber collected in real time by a plasma concentration sensor or detection device, which can be measured by an optical emission spectrometer or a probe array. The second plasma concentration distribution data is used to reflect the distribution state of the plasma in space. The optimal cleaning path refers to the optimal motion trajectory calculated according to the plasma concentration distribution data to cover all the regions to be cleaned on the surface of the graphite boat. The optimal cleaning path can be generated by algorithm analysis of the concentration gradient combined with the structural characteristics of the graphite boat to ensure that there is no omission in the cleaning process. Adjusting the first current and the second current refers to changing the current intensity difference of the two electrodes to control the electric field distribution and the direction of plasma movement. A programmable power supply module can be used to adjust the output parameters so that the plasma moves along the predetermined path.

[0058] In the cleaning process, the plasma concentration distribution in the sealed chamber is monitored in real time. When it is detected that the local region has too high or too low concentration, the system automatically generates an optimal path covering the low concentration region, and changes the electric field intensity gradient by adjusting the current ratio of the two electrodes to drive the plasma to move along the path on the surface of the graphite boat. For example, when it is detected that the plasma concentration of the edge region of the graphite boat is insufficient, the path planning algorithm preferentially guides the plasma to move towards the edge, and at the same time forms a directional electric field by increasing the current of the first electrode and reducing the current of the second electrode to promote the high-energy ions to continuously bombard the contaminants along the edge path.

[0059] The prior art plasma cleaning usually adopts a fixed electric field distribution, which cannot effectively cover the regions with uneven concentration. The embodiment can actively guide the plasma to concentrate in weak regions by dynamically monitoring the concentration data and adjusting the current parameters in real time, thereby avoiding cleaning dead angles caused by uneven distribution. The cleaning method in the prior art relies on a single electric field direction or a fixed frequency, which is difficult to adapt to the surface topography of a complex structure graphite boat. The embodiment realizes adaptive cleaning of the special-shaped surface through path planning and current cooperative control.

[0060] Through the above technical solutions, the embodiment solves the problem of incomplete cleaning caused by uneven plasma distribution. By dynamically adjusting the path and current parameters, the high-energy ions can accurately cover each region on the surface of the graphite boat, which is especially suitable for graphite boats with grooves, holes or complex geometrical shapes, effectively removes stubborn residues such as silicon nitride, and at the same time avoids material damage caused by local over-cleaning.

[0061] Optionally, referring to Figure 7 , another embodiment of the present application provides a cleaning method for a graphite boat, based on the above Figure 1 embodiment, the sealed chamber comprises a transfer chamber and a cleaning chamber, and a passage door is arranged between the transfer chamber and the cleaning chamber. The cleaning method of the graphite boat further includes steps S900-S1000, wherein: S900, before cleaning, opening the transfer chamber and sending the graphite boat to be cleaned into the transfer chamber; S1000, after the transfer chamber is vacuumized, opening the passage door between the transfer chamber and the cleaning chamber to control the graphite boat to be cleaned to be transferred from the transfer chamber to the cleaning chamber for cleaning.

[0062] The transfer chamber refers to an independent pre-treatment space connected with the cleaning chamber, which can be made of metal or ceramic material to realize a sealed structure, and the transfer chamber is used to complete preliminary environmental isolation before the graphite boat enters the cleaning chamber. The passage door refers to a controllable opening and closing device connecting the two chambers, which can be realized by a gate valve structure driven by gas or electricity, and is used to realize the material transfer between the two chambers after vacuumization. The vacuumization refers to the process of discharging the gas in the transfer chamber to a set pressure range by a vacuum pump, which can be realized by a vacuum system combined with a mechanical pump and a molecular pump, and is used to eliminate the interference of air residues on the subsequent cleaning process.

[0063] Before the cleaning process starts, the graphite boat is first sent into the transfer chamber for loading, and then the transfer chamber inlet is closed and vacuumized. When the vacuum degree reaches a predetermined threshold, the passage door is automatically opened, and the graphite boat is smoothly transferred to the cleaning chamber by a mechanical conveying device. In this process, the transfer chamber acts as a transition area, effectively preventing the pollution of the external environment to the sealed chamber, and avoiding the decline of plasma stability caused by direct exposure to the atmosphere by adjusting the pressure in stages.

[0064] The traditional cleaning equipment directly places the graphite boat in an open environment and sends it into the cleaning chamber, which is easy to introduce particle pollutants and cause chamber pressure fluctuations. By setting an independent transfer chamber and step-by-step vacuumization, the embodiment not only ensures the cleanliness of the material transfer process, but also maintains the best vacuum environment required for plasma generation. The embodiment realizes the environmental isolation control of the graphite boat during the transfer process, effectively reduces the risk of the cleaning chamber being invaded by external pollutants, and ensures the stability of the plasma excitation process through step-by-step pressure adjustment, thereby improving the reliability and repeatability of the cleaning process.

[0065] Optionally, referring to Figure 8 , another embodiment of the present application provides a cleaning method of a graphite boat, based on the above Figure 1 embodiment, the cleaning method of the graphite boat further includes steps S1100-S1300, wherein: S1100, obtaining current temperature data and pressure data of the sealed chamber; S1200, determining first cleaning parameters corresponding to the temperature data and the pressure data; S1300, determine the conversion frequency of the power source according to the first cleaning parameter, to adjust the movement speed of the plasma on the surface of the graphite boat.

[0066] Wherein, the temperature data refers to the temperature value inside the closed chamber collected by the temperature sensor in real time, which can be realized by using a thermocouple or an infrared temperature measurement module, and the temperature data is used to reflect the temperature change of the plasma generation environment. The pressure data refers to the gas pressure value inside the closed chamber collected by the pressure sensor in real time, which can be realized by using a piezoresistive or capacitive pressure sensor, and the pressure data is used to monitor the ionization state of the gas. The first cleaning parameter refers to the frequency adjustment parameter generated according to the correlation between temperature and pressure, which can be generated by a preset mapping table or a calculation model, and the first cleaning parameter is used to dynamically match the plasma excitation condition. The preset frequency refers to the alternating current signal frequency initially set by the power source, which can be set based on historical process data, and is used to control the plasma generation intensity and ion movement direction.

[0067] Wherein, during the cleaning process, the temperature sensor and the pressure sensor continuously collect the environmental parameters inside the closed chamber. When the temperature rises to cause the gas ionization efficiency to change, or the pressure fluctuates to affect the plasma distribution, the system obtains the corresponding frequency correction amount by looking up the table or calculating according to the comparison result of the real-time data and the preset threshold. For example, if it is detected that the temperature rises above the threshold, the preset frequency is reduced to reduce the ion kinetic energy, so as to avoid damage to the surface of the graphite boat caused by the temperature being too high; if the pressure drops to a critical range, the frequency is increased to enhance the electric field intensity, so as to maintain the plasma concentration. By periodically adjusting the frequency, the ion movement speed is adapted to the current environmental parameters, so that stable cleaning effect is realized on the premise of avoiding material damage.

[0068] Compared with the prior art, the traditional method usually uses an alternating current power supply with a fixed frequency, which cannot dynamically adjust the plasma state according to the change of the chamber environment, and is prone to cause the cleaning efficiency to decrease or the material to be damaged due to the temperature or pressure fluctuation. The embodiment can actively adapt to the change of the process condition by real-time monitoring of the environmental parameters and linkage adjustment of the frequency, so as to ensure that the plasma movement speed is always in a reasonable range.

[0069] Through the above technical solution, the embodiment solves the problem of unstable plasma energy caused by the temperature or pressure fluctuation of the chamber, and the ion movement speed is adapted to the current environment by dynamically adjusting the frequency, which not only avoids the damage to the surface of the graphite boat caused by the ion kinetic energy being too high under the condition of high temperature or low pressure, but also prevents the incomplete removal of residues caused by the decrease of the cleaning efficiency under the condition of low temperature or high pressure.

[0070] Optionally, referring to Figure 9 The present application also provides a cleaning method of a graphite boat based on the above Figure 1In the illustrated embodiment, the graphite boat cleaning method further includes steps S1400-S1500, in which: S1400, in response to the second cleaning parameter input by the user, obtaining a frequency deviation value between the frequency in the second cleaning parameter and the current frequency of the power source; S1500, correcting the current frequency of the power source according to the frequency deviation value to adjust the movement speed of the plasma on the surface of the graphite boat.

[0071] The second cleaning parameter refers to a set of operating parameters set by the user according to actual working conditions, which can be input by a man-machine interface or a preset mode, such as inputting a target frequency value through a touch screen or selecting a quick cleaning mode. The frequency deviation value refers to the difference between the user-set frequency and the current frequency of the device, which can be monitored and output in real time by a difference calculation module, such as generating a deviation signal by a microprocessor after subtracting the two sets of data. Correcting the current frequency refers to dynamically adjusting the output frequency of the power source based on the deviation value, which can be achieved by a closed-loop feedback control system, such as phase compensation and amplitude correction of the power source output waveform by a PID controller.

[0072] When the user inputs the second cleaning parameter containing the target frequency through the operation interface, the control device will collect the current frequency of the power source in real time and calculate the frequency deviation value between the two. After the deviation value is transmitted to the frequency adjustment module, the output frequency of the power source will be dynamically adjusted according to the deviation proportion. For example, when the user input frequency is higher than the preset value, the output frequency of the power source is gradually increased, so that the movement speed of the charged particles in the plasma is accelerated, thereby enhancing the impact effect on the stubborn deposits on the surface of the graphite boat; conversely, when the input frequency is lower than the current value, the output frequency of the power source is reduced to reduce the kinetic energy of the ions, avoiding excessive etching of the graphite boat substrate. In this process, the control device continuously monitors the frequency deviation change until the actual output frequency and the user-set value reach a dynamic equilibrium state.

[0073] Compared with the prior art, the frequency parameter of the traditional plasma cleaning equipment is usually fixed or only supports limited gear adjustment, which cannot flexibly adjust the ion movement speed according to the on-site working conditions. The embodiment introduces a user interaction interface and a real-time frequency correction mechanism, allowing the operator to directly intervene in the ion kinetic energy parameters during the cleaning process, such as temporarily increasing the frequency to enhance the cleaning strength when encountering special pollutants, or reducing the frequency to prevent damage when processing thin-layer structures. This dynamic adjustment capability overcomes the adaptability problem caused by the fixed cleaning parameters in the prior art.

[0074] By the technical solution, the control on the plasma movement speed is accurate, and the cleaning intensity of different areas on the graphite boat surface can be differentiated according to actual requirements. For example, the ion impact force can be enhanced by increasing the frequency in the area with dense groove structures, and the frequency can be reduced in the planar area to maintain uniform cleaning. The dynamic adjustment mechanism based on the user input effectively solves the problem of insufficient or excessive cleaning in the local area of the graphite boat with complex structures.

[0075] The application further provides a control device, which comprises a memory, a processor and a graphite boat cleaning program stored in the memory and executable on the processor, and the graphite boat cleaning program is configured to implement the graphite boat cleaning method.

[0076] It is worth noting that, since the control device is based on the graphite boat cleaning method, the embodiments of the control device include all the technical solutions of all the embodiments of the graphite boat cleaning method, and the technical effects are also completely the same, which will not be repeated here.

[0077] The application further provides a graphite boat cleaning device, which comprises the control device as described in the above embodiments.

[0078] It is worth noting that, since the graphite boat cleaning device is based on the control device, the embodiments of the graphite boat cleaning device include all the technical solutions of all the embodiments of the control device, and the technical effects are also completely the same, which will not be repeated here.

[0079] It should be noted that, in this document, the terms "comprising" and "including" or any other variant thereof are intended to cover non-exclusive inclusions, so that the process, method, article or system including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or further includes the elements inherent to such process, method, article or system. Without more limitations, the element defined by the statement "comprising a" does not exclude the presence of other identical elements in the process, method, article or system including the element.

[0080] The above-mentioned embodiment numbers of the application are only for description, and do not represent the advantages and disadvantages of the embodiments.

[0081] Those skilled in the art can clearly understand the above-mentioned embodiment method can be realized by means of software and the necessary general hardware platform, of course, also can be through hardware, but in many cases the former is the better embodiment. Based on such understanding, the technical solutions of the present application essentially or say the part of the contribution to the prior art can be embodied in the form of software products, the computer software product is stored in a storage medium (such as ROM / RAM, magnetic disc, optical disc) as described above, including a number of instructions to make a terminal device (may be a mobile phone, computer, server, or network equipment, etc.) executes the method described in various embodiments of the present application.

[0082] The above is only the preferred embodiment of the present application, not therefore limit the patent scope of the present application, any equivalent structure or equivalent flow transformation made by using the content of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A graphite boat cleaning method capable of being applied to graphite boat dry cleaning, characterized in that: a first electrode is arranged on the inner wall of a closed chamber, and a second electrode is arranged opposite to the first electrode, the first electrode and the second electrode are connected to two poles of the same power source; a gas material introduced into the closed chamber is excited by an electric field generated by the first electrode and the second electrode of the power source to generate a plasma, and the graphite boat placed between the first electrode and the second electrode is cleaned by the plasma; and the power source is an alternating current signal. The control of the power source to generate an electric field by the first electrode and the second electrode to excite the gas material introduced into the closed chamber to generate a plasma, and the graphite boat placed between the first electrode and the second electrode is cleaned by the plasma, comprises: obtaining a first operating frequency of the power source, determining a first transformation time corresponding to the first operating frequency; controlling the power source to generate an electric field in a first direction by the first electrode and the second electrode, so that the charged ions and groups in the plasma for cleaning move along the first direction; in the case that the first power source transformation time reaches a threshold value, the power source polarity is transformed, so that the first electrode and the second electrode generate an electric field in a second direction, so that the positively charged ions or groups in the plasma move along the second direction, and the first direction and the second direction are opposite directions; and the power source polarity output by the power source is transformed according to the first power source transformation time, so that the positively charged ions or groups in the plasma move along the first direction and the second direction. The power source comprises an ignition direct current source.

2. The method of cleaning a graphite boat according to claim 1, wherein The control of the power source to generate an electric field by the first electrode and the second electrode to excite the gas material introduced into the closed chamber to generate a plasma, specifically comprises: determining a plurality of zero point positions of the first transformation time; in the case that each first transformation time is at the zero point position, the ignition direct current source is connected to the first electrode and the second electrode to control the gas material introduced into the closed chamber to generate a plasma. The control of the power source to generate an electric field by the first electrode and the second electrode to excite the gas material introduced into the closed chamber to generate a plasma, and the graphite boat placed between the first electrode and the second electrode is cleaned by the plasma, comprises: obtaining a plurality of second operating frequencies corresponding to a plurality of cleaning stages of the power source, determining a second transformation time corresponding to the second operating frequency, and the second operating frequencies corresponding to the plurality of cleaning stages are arranged in a descending trend in time sequence; and the positive and negative voltages applied to the first electrode and the second electrode are transformed according to the second power source transformation time, so that the charged ions and groups in the plasma for cleaning move along the electric field direction. The graphite boat cleaning method further comprises: obtaining first plasma concentration distribution data of the closed chamber, and determining an aggregation position of the plasma; determining a first distance between the aggregation position and the first electrode, and a second distance between the aggregation position and the second electrode; ​ ​ 3. The method of cleaning a graphite boat according to claim 2, wherein ​ ​ ​ ​ 4. The method of cleaning a graphite boat according to claim 1, wherein ​ ​ ​ 5. The method of cleaning a graphite boat according to claim 1, wherein ​ ​ ​ According to the size relationship between the first distance and the second distance, the power supply polarity output by the first electrode and the second electrode is adjusted so that the first distance and the second distance gradually tend to be equal.

6. The method of cleaning a graphite boat according to claim 1, wherein The graphite boat cleaning method further comprises: obtaining current second plasma concentration distribution data of the sealed chamber; determining an optimal cleaning path corresponding to the plasma concentration distribution data; adjusting the first current output by the first electrode and the second current output by the second electrode according to the optimal cleaning path, so as to drive the plasma to move on the surface of the graphite boat along the direction of the electric field corresponding to the optimal cleaning path.

7. The method of cleaning a graphite boat according to claim 1, wherein The sealed chamber comprises a transfer chamber and a cleaning chamber, and a passage door is arranged between the transfer chamber and the cleaning chamber. The graphite boat cleaning method further comprises: before cleaning, opening the transfer chamber and sending the graphite boat to be cleaned into the transfer chamber; after the transfer chamber is vacuumized, opening the passage door between the transfer chamber and the cleaning chamber to control the graphite boat to be cleaned to be transferred from the transfer chamber to the cleaning chamber for cleaning.

8. The method of cleaning a graphite boat of claim 1, wherein, The graphite boat cleaning method further comprises: obtaining current temperature data and pressure data of the sealed chamber; determining first cleaning parameters corresponding to the temperature data and the pressure data; determining the transformation frequency of the power source according to the first cleaning parameters, so as to adjust the movement speed of the plasma on the surface of the graphite boat; The graphite boat cleaning method further comprises: in response to the second cleaning parameters input by the user, obtaining a frequency deviation value of the frequency in the second cleaning parameters from the current frequency of the power source; correcting the current frequency of the power source according to the frequency deviation value, so as to adjust the movement speed of the plasma on the surface of the graphite boat.

9. A control device characterized by comprising: The control device comprises a memory, a processor, and a graphite boat cleaning program stored on the memory and executable on the processor, and the graphite boat cleaning program is configured to implement the graphite boat cleaning method according to any one of claims 1 to 8.

10. A cleaning apparatus for graphite boats, characterized by, The graphite boat cleaning device comprises the control device according to claim 9, and the graphite boat cleaning device is used for graphite boat dry cleaning. The graphite boat cleaning device comprises the control device according to claim 9, and the graphite boat cleaning device is used for graphite boat dry cleaning.

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