Graphite boat cleaning process

Abstract

The graphite boat cleaning process comprises the following specific steps that S1, a graphite boat is disassembled, specifically, the graphite boat is disassembled, and graphite boat parts are separated; s2, pickling the graphite boat: putting the graphite boat into a pickling tank, and soaking and cleaning the graphite boat with a pickling solution; s3, fluidized bed cleaning: cleaning the pickled graphite boat by using a zeolite powder fluidized bed; the step S3 of cleaning the fluidized bed comprises the following specific steps: S31, starting the fluidized bed; s32, the air volume is adjusted; s33, setting the temperature; s34, a combustor is ignited; s35, fully paving the materials; s36, placing a graphite boat; s37, washing the zeolite powder; s38, taking out; s39, oscillating and filtering; the graphite boat cleaning process provided by the invention has the technical effects that hydrofluoric acid residues on the graphite boat can be avoided, and thoroughness in cleaning is guaranteed. The graphite boat cleaning process has the advantages that hydrofluoric acid residues on the graphite boat can be avoided, and thoroughness in cleaning is guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of graphite boat cleaning, and in particular to a graphite boat cleaning process. Background Art

[0002] Plasma enhanced chemical vapor deposition is an indispensable part of the silicon solar cell manufacturing process. With the continuous improvement of PECVD technology, tubular PECVD has significantly improved the efficiency of solar cells. The cleaning effect of the graphite boat has a significant impact on the effect of tubular PECVD coating.

[0003] During the graphite boat cleaning process, the graphite boat needs to be immersed in the pickling solution. During the immersion process, the pickling solution will penetrate into the inside of the graphite boat. Even after subsequent cleaning, hydrofluoric acid may remain on the inner wall of the graphite boat. The hydrofluoric acid remains on the surface of the graphite boat and corrodes the graphite boat for a long time, which will affect the process points where the graphite boat contacts the silicon wafer. Summary of the invention

[0004] The invention discloses a graphite boat cleaning process, aiming to solve the technical problem that hydrofluoric acid remains on the surface of the graphite boat, corrodes the graphite boat for a long time, and affects the process stuck points on the graphite boat that contact with silicon wafers.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A graphite boat cleaning process comprises the following specific steps:

[0007] S1: Graphite boat disassembly: disassemble the graphite boat and separate the graphite boat components;

[0008] S2: Pickling of graphite boat: putting the graphite boat into the pickling tank and soaking and cleaning the graphite boat with the pickling liquid;

[0009] S3: Fluidized bed cleaning: Use zeolite powder fluidized bed to clean the graphite boat after pickling;

[0010] S4: Cold water washing: The graphite boat after fluidized bed washing is transferred to a cold water tank and washed with cold water;

[0011] S5: hot water washing: the graphite boat after cold water washing is transferred to a hot water washing tank, and the graphite boat is washed again with hot water;

[0012] S6: Blowing: Use high-speed wind flow to clean the surface of the graphite boat after hot water washing, so that the water droplets and other adherents attached to the surface of the graphite boat are separated from the surface of the graphite boat;

[0013] S7: Drying: Drying the graphite boat using a dryer;

[0014] The fluidized bed cleaning step S3 comprises the following specific steps:

[0015] S31: fluidized bed start-up;

[0016] S32: Adjust air volume: Start the induced draft fan of the fluidized bed and adjust the induced draft fan air volume according to the height of the graphite boat and the injection amount of zeolite powder;

[0017] S33: Set temperature: set the initial temperature through the temperature controller;

[0018] S34: Burner ignition: control the ignition switch to ignite the burner at the ignition position;

[0019] S35: Spreading materials: Spreading zeolite powder in the fluidized bed, and using tools to help spread the zeolite powder evenly;

[0020] S36: placing the graphite boat: placing the acid-washed graphite boat into the zeolite powder in the fluidized bed;

[0021] S37: zeolite powder cleaning: zeolite powder is wrapped on the surface of the graphite boat to clean the graphite boat and absorb the residual hydrofluoric acid on the surface of the graphite boat;

[0022] S38: Taking out: taking out the graphite boat in the zeolite powder;

[0023] S39: Oscillation filtration: The zeolite powder adhering to the surface of the graphite boat is shed by oscillation, and the shed zeolite powder is filtered, and the filtered zeolite powder is returned to the fluidized bed for standby use;

[0024] In S35, the laying height of the zeolite powder must meet the height of the graphite boat, so that the graphite boat is completely immersed in the zeolite powder;

[0025] In S33, the initial temperature is set to 70°C;

[0026] In S37, the cleaning time of the graphite boat placed in the zeolite powder is controlled to be 3-5 minutes.

[0027] By using a zeolite powder fluidized bed to clean the graphite boat, the hydrofluoric acid on the surface of the graphite boat can be adsorbed. Zeolite powder is a natural or synthetic porous material that has excellent adsorption effect on hydrofluoric acid. The graphite boat is pre-cleaned using a zeolite powder fluidized bed before cleaning with clean water, so that the zeolite powder can penetrate into the graphite boat. Based on the contact between the graphite boat and the zeolite powder and the effect of the fluidized bed, the stubborn stains adhering to the surface of the graphite boat fall off. At the same time, the zeolite powder can also quickly adsorb the hydrofluoric acid remaining on the graphite boat, thereby achieving the dual effects of cleaning stubborn stains and cleaning with hydrofluoric acid, which can ensure the cleaning effect of the graphite boat and avoid the corrosion of the graphite boat surface by residual acidic substances.

[0028] In a preferred embodiment, the S4, cold water washing comprises the following specific steps:

[0029] S41: preparing a cold water washing liquid: mixing sodium hydroxide and cold water according to a certain proportion to prepare a cold water washing liquid;

[0030] S42: placing in a cold water washing tank: uniformly mixing the cold water washing liquid in the cold water washing tank;

[0031] S43: Placing the graphite boat: transferring the graphite boat after vibration filtration to a cold water washing tank, and immersing it completely in the cold water washing liquid;

[0032] S44: Ultrasonic vibration cleaning: The graphite boat is cleaned in a cold water washing tank using ultrasonic waves;

[0033] S45: Taking out: taking out the graphite boat in the cold water washing tank;

[0034] S46: filtering zeolite powder: filtering the zeolite powder in the cold water washing liquid;

[0035] In the S41, the ratio of sodium hydroxide to cold water in the cold water washing liquid is 1:8-12;

[0036] The S46 comprises the following specific steps:

[0037] S461: discharge cold water washing liquid;

[0038] S462: Collecting zeolite powder: During the discharge of the cold water washing liquid, the zeolite powder is separated by a filter and collected;

[0039] S463: Deionized water rinsing: rinsing the zeolite powder again with deionized water to remove the alkali solution;

[0040] S464: drying zeolite powder: drying the zeolite powder using a dryer;

[0041] In S2, the pickling solution in the pickling of the graphite boat is prepared by mixing hydrofluoric acid and hydrogen peroxide, and the ratio of hydrofluoric acid to hydrogen peroxide is 1:2.

[0042] By adding sodium hydroxide during the cold water washing process, when the sodium hydroxide is mixed with cold water to clean the graphite boat, in addition to neutralizing possible residual acidic substances, the zeolite powder adhering to the surface of the graphite boat can also be thoroughly cleaned. In addition, when using alkaline solution for cleaning, the zeolite powder and the graphite boat can be cleaned simultaneously. Then, the zeolite powder is filtered out, and the alkaline solution adsorbed in the zeolite powder can be washed away with deionized water and dried, thereby realizing the treatment of the zeolite powder. The treated zeolite powder can be used again. In order to ensure the adsorption of hydrofluoric acid by the zeolite powder, the quality requirements of the zeolite powder used are relatively high, and the cost is also relatively high. The function of the zeolite powder can be restored by secondary treatment of the zeolite powder, thereby achieving the purpose of reducing costs.

[0043] As can be seen from the above, a graphite boat cleaning process includes the following specific steps: S1: graphite boat disassembly: disassembling the graphite boat and separating the graphite boat parts; S2: graphite boat pickling: putting the graphite boat into the pickling tank and soaking and cleaning the graphite boat with the pickling liquid; S3: fluidized bed cleaning: using a zeolite powder fluidized bed to clean the graphite boat after pickling; S4: cold water washing: the graphite boat after fluidized bed cleaning is transferred to a cold water tank and cleaned with cold water washing liquid; S5: hot water washing: the graphite boat after cold water washing is transferred to a hot water cleaning tank and cleaned again with hot water; S6: purging: using a high-speed wind flow to clean the surface of the graphite boat after hot water washing, so that the water droplets and other adherents attached to the surface are separated from the surface of the graphite boat; S7: drying: using a dryer to dry the graphite boat;

[0044] The fluidized bed cleaning in S3 includes the following specific steps: S31: fluidized bed startup; S32: air volume adjustment: start the fluidized bed induced draft fan, and adjust the induced draft fan air volume according to the graphite boat height and the zeolite powder injection amount; S33: set temperature: set the initial temperature through the temperature controller; S34: burner ignition: control the ignition switch to ignite the burner ignition position; S35: spread the material: spread the zeolite powder in the fluidized bed, and use tools to help the zeolite powder be evenly spread; S36: Place graphite boat: place the acid-washed graphite boat into the zeolite powder in the fluidized bed; S37: Wash zeolite powder: wrap the zeolite powder on the surface of the graphite boat, wash the graphite boat, and absorb the residual hydrofluoric acid on the surface of the graphite boat; S38: Take out: take out the graphite boat in the zeolite powder; S39: Oscillation filtration: oscillate to make the zeolite powder adhered to the surface of the graphite boat fall off, filter the fallen zeolite powder, and return the filtered zeolite powder to the fluidized bed for standby use. The graphite boat washing process provided by the present invention has the technical effect of avoiding hydrofluoric acid residue on the graphite boat and ensuring the thoroughness of washing. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 The present invention provides an overall flow chart of a graphite boat cleaning process.

[0046] Figure 2 The present invention provides a flow chart of fluidized bed cleaning of a graphite boat cleaning process.

[0047] Figure 3 The present invention provides a cold water washing flow chart for a graphite boat cleaning process.

[0048] Figure 4 The present invention provides a flow chart for filtering zeolite powder in a graphite boat cleaning process. DETAILED DESCRIPTION

[0049] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0050] A graphite boat cleaning process disclosed in the present invention is mainly used in the scenario of graphite boat cleaning.

[0051] Reference Figure 1 and Figure 2 , a graphite boat cleaning process, comprising the following specific steps:

[0052] S1: Graphite boat disassembly: disassemble the graphite boat and separate the graphite boat components;

[0053] S2: Pickling of graphite boat: putting the graphite boat into the pickling tank and soaking and cleaning the graphite boat with the pickling liquid;

[0054] S3: Fluidized bed cleaning: Use zeolite powder fluidized bed to clean the graphite boat after pickling;

[0055] S4: Cold water washing: The graphite boat after fluidized bed washing is transferred to a cold water tank and washed with cold water;

[0056] S5: hot water washing: the graphite boat after cold water washing is transferred to a hot water washing tank, and the graphite boat is washed again with hot water;

[0057] S6: Blowing: Use high-speed wind flow to clean the surface of the graphite boat after hot water washing, so that the water droplets and other adherents attached to the surface of the graphite boat are separated from the surface of the graphite boat;

[0058] S7: Drying: Drying the graphite boat using a dryer;

[0059] S3, fluidized bed cleaning includes the following specific steps:

[0060] S31: fluidized bed start-up;

[0061] S32: Adjust air volume: Start the induced draft fan of the fluidized bed and adjust the induced draft fan air volume according to the height of the graphite boat and the injection amount of zeolite powder;

[0062] S33: Set temperature: set the initial temperature through the temperature controller;

[0063] S34: Burner ignition: control the ignition switch to ignite the burner at the ignition position;

[0064] S35: Spreading materials: Spreading zeolite powder in the fluidized bed, and using tools to help spread the zeolite powder evenly;

[0065] S36: placing the graphite boat: placing the acid-washed graphite boat into the zeolite powder in the fluidized bed;

[0066] S37: zeolite powder cleaning: zeolite powder is wrapped on the surface of the graphite boat to clean the graphite boat and absorb the residual hydrofluoric acid on the surface of the graphite boat;

[0067] S38: Taking out: taking out the graphite boat in the zeolite powder;

[0068] S39: Oscillation filtration: The zeolite powder adhered to the surface of the graphite boat is shed by oscillation, and the shed zeolite powder is filtered. The filtered zeolite powder is returned to the fluidized bed for standby use. The graphite boat is cleaned by using the zeolite powder fluidized bed to adsorb the hydrofluoric acid on the surface of the graphite boat. Specifically, based on the characteristics of zeolite powder, zeolite powder is a natural or synthetic porous material with excellent adsorption effect on hydrofluoric acid. During the pickling process, the graphite boat needs to be immersed in a pickling solution made of hydrofluoric acid. During the soaking process, the pickling solution will penetrate into the graphite boat, including various dead corners. If it is only cleaned with clean water, the pickling solution may cause The hydrofluoric acid in the graphite boat adheres to the surface of the graphite boat, affecting the process bottleneck of the graphite boat contacting the silicon wafer. Therefore, the graphite boat is pre-cleaned using a zeolite powder fluidized bed before cleaning with clean water. The zeolite powder is blown up by the airflow of the fluidized bed so that the zeolite powder can penetrate into the graphite boat. Based on the contact between the graphite boat and the zeolite powder and the effect of the fluidized bed, the zeolite powder in an active state can act on the surface of the graphite boat to remove the stubborn stains adhered to the surface. At the same time, the zeolite powder can also quickly absorb the residual hydrofluoric acid on the graphite boat, thereby achieving the dual effects of cleaning stubborn stains and cleaning with hydrofluoric acid, which can ensure the cleaning effect of the graphite boat and avoid the corrosion of the graphite boat surface by residual acidic substances.

[0069] Reference Figure 2 In a preferred embodiment, in S35, the laying height of the zeolite powder needs to meet the height of the graphite boat, so that the graphite boat is completely immersed in the zeolite powder.

[0070] Reference Figure 2 In a preferred embodiment, in S33, the initial temperature is set to 70°C.

[0071] Reference Figure 2In a preferred embodiment, in S37, the cleaning time of the graphite boat placed in the zeolite powder is controlled to be 3-5 minutes.

[0072] Reference Figure 3 In a preferred embodiment, S4, cold water washing comprises the following specific steps:

[0073] S41: preparing a cold water washing liquid: mixing sodium hydroxide and cold water according to a certain proportion to prepare a cold water washing liquid;

[0074] S42: placing in a cold water washing tank: uniformly mixing the cold water washing liquid in the cold water washing tank;

[0075] S43: Placing the graphite boat: transferring the graphite boat after vibration filtration to a cold water washing tank, and immersing it completely in the cold water washing liquid;

[0076] S44: Ultrasonic vibration cleaning: The graphite boat is cleaned in a cold water washing tank using ultrasonic waves;

[0077] S45: Taking out: taking out the graphite boat in the cold water washing tank;

[0078] S46: filtering zeolite powder: filtering the zeolite powder in the cold water washing liquid.

[0079] Reference Figure 3 In a preferred embodiment, in S41, the ratio of sodium hydroxide to cold water in the cold water washing liquid is 1:8-12.

[0080] Reference Figure 4 In a preferred embodiment, S46 includes the following specific steps:

[0081] S461: discharge cold water washing liquid;

[0082] S462: Collecting zeolite powder: During the discharge of the cold water washing liquid, the zeolite powder is separated by a filter and collected;

[0083] S463: Deionized water rinsing: rinsing the zeolite powder again with deionized water to remove the alkali solution;

[0084] S464: Zeolite powder drying: The zeolite powder is dried using a dryer. Sodium hydroxide is added during the cold water washing process. Since sodium hydroxide is an alkaline substance, when it is mixed with cold water to clean the graphite boat, in addition to neutralizing possible residual acidic substances, the zeolite powder adhering to the surface of the graphite boat can also be thoroughly cleaned to avoid the presence of zeolite powder affecting the process bottleneck of the graphite boat. In addition, the zeolite powder treated with alkali solution can simultaneously achieve the characteristics of increasing specific surface area and porosity, improving adsorption performance and chemical stability, and enhancing the catalytic activity of the zeolite powder. Therefore, when using alkali solution for cleaning, the zeolite powder and the graphite boat can be cleaned simultaneously. Then, the zeolite powder is filtered out, and the alkali solution adsorbed in the zeolite powder can be washed off with deionized water and dried, thereby realizing the treatment of the zeolite powder. The treated zeolite powder can be used again. In order to ensure the adsorption of hydrofluoric acid by the zeolite powder, the quality requirements of the zeolite powder used are high, and the cost is also high. The function of the zeolite powder can be restored by secondary treatment of the zeolite powder, thereby achieving the purpose of reducing costs.

[0085] Reference Figure 1 In a preferred embodiment, S2, the pickling solution in the pickling of the graphite boat is prepared by mixing hydrofluoric acid and hydrogen peroxide, and the ratio of hydrofluoric acid to hydrogen peroxide is 1:2.

[0086] Working principle: By using a zeolite powder fluidized bed to clean the graphite boat, the hydrofluoric acid on the surface of the graphite boat can be adsorbed. Specifically, based on the characteristics of zeolite powder, zeolite powder is a natural or synthetic porous material with excellent adsorption of hydrofluoric acid. During the pickling process, the graphite boat needs to be immersed in a pickling solution made of hydrofluoric acid. During the soaking process, the pickling solution will penetrate into the graphite boat, including all dead corners. If it is only cleaned with water, the hydrofluoric acid in the pickling solution may adhere to the surface of the graphite boat, affecting the contact between the graphite boat and the silicon wafer. Art card point, thus, the graphite boat is pre-cleaned with a zeolite powder fluidized bed before cleaning with clean water, and the zeolite powder is blown up by the airflow of the fluidized bed so that the zeolite powder can penetrate into the graphite boat. Based on the contact between the graphite boat and the zeolite powder and the effect of the fluidized bed, the zeolite powder in the active state can act on the surface of the graphite boat to remove the stubborn stains adhering to the surface of the graphite boat, and at the same time, the zeolite powder can also quickly absorb the hydrofluoric acid remaining on the graphite boat, thereby achieving the dual effects of cleaning stubborn stains and cleaning with hydrofluoric acid, which can ensure the cleaning effect of the graphite boat and avoid the corrosion of the graphite boat surface by residual acidic substances.

[0087] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A graphite boat cleaning process, characterized in that: The specific steps include: S1: Graphite boat disassembly: disassemble the graphite boat and separate the graphite boat components; S2: Pickling of graphite boat: putting the graphite boat into the pickling tank and soaking and cleaning the graphite boat with the pickling liquid; S3: Fluidized bed cleaning: Use zeolite powder fluidized bed to clean the graphite boat after pickling; S4: Cold water washing: The graphite boat after fluidized bed washing is transferred to a cold water tank and washed with cold water; S5: hot water washing: the graphite boat after cold water washing is transferred to a hot water washing tank, and the graphite boat is washed again with hot water; S6: Blowing: Use high-speed wind flow to clean the surface of the graphite boat after hot water washing, so that the water droplets and other adherents attached to the surface of the graphite boat are separated from the surface of the graphite boat; S7: Drying: Drying the graphite boat using a dryer; The fluidized bed cleaning step S3 comprises the following specific steps: S31: fluidized bed start-up; S32: Adjust air volume: Start the induced draft fan of the fluidized bed and adjust the induced draft fan air volume according to the height of the graphite boat and the injection amount of zeolite powder; S33: Set temperature: set the initial temperature through the temperature controller; S34: Burner ignition: control the ignition switch to ignite the burner at the ignition position; S35: Spreading materials: Spreading zeolite powder in the fluidized bed, and using tools to help spread the zeolite powder evenly; S36: placing the graphite boat: placing the acid-washed graphite boat into the zeolite powder in the fluidized bed; S37: zeolite powder cleaning: zeolite powder is wrapped on the surface of the graphite boat to clean the graphite boat and absorb the residual hydrofluoric acid on the surface of the graphite boat; S38: Taking out: taking out the graphite boat in the zeolite powder; S39: Oscillation filtration: The zeolite powder adhering to the surface of the graphite boat is shed by oscillation, and the shed zeolite powder is filtered. The filtered zeolite powder is returned to the fluidized bed for standby use.

2. A graphite boat cleaning process according to claim 1, characterized in that: In the above S35, the laying height of the zeolite powder must meet the height of the graphite boat, so that the graphite boat is completely immersed in the zeolite powder.

3. A graphite boat cleaning process according to claim 1, characterized in that: In S33, the initial temperature is set to 70°C.

4. A graphite boat cleaning process according to claim 1, characterized in that: In S37, the cleaning time of the graphite boat placed in the zeolite powder is controlled to be 3-5 minutes.

5. A graphite boat cleaning process according to claim 1, characterized in that: The cold water washing in S4 comprises the following specific steps: S41: preparing a cold water washing liquid: mixing sodium hydroxide and cold water according to a certain proportion to prepare a cold water washing liquid; S42: placing in a cold water washing tank: uniformly mixing the cold water washing liquid in the cold water washing tank; S43: Placing the graphite boat: transferring the graphite boat after vibration filtration to a cold water washing tank, and immersing it completely in the cold water washing liquid; S44: Ultrasonic vibration cleaning: The graphite boat is cleaned in a cold water washing tank using ultrasonic waves; S45: Taking out: taking out the graphite boat in the cold water washing tank; S46: filtering zeolite powder: filtering the zeolite powder in the cold water washing liquid.

6. A graphite boat cleaning process according to claim 5, characterized in that: In S41, the ratio of sodium hydroxide to cold water in the cold water washing liquid is 1:8-12.

7. A graphite boat cleaning process according to claim 5, characterized in that: The S46 comprises the following specific steps: S461: discharge cold water washing liquid; S462: Collecting zeolite powder: During the discharge of the cold water washing liquid, the zeolite powder is separated by a filter and collected; S463: Deionized water rinsing: rinsing the zeolite powder again with deionized water to remove the alkali solution; S464: Drying of zeolite powder: Drying of zeolite powder by a dryer.

8. A graphite boat cleaning process according to claim 1, characterized in that: In S2, the pickling solution in the pickling of the graphite boat is prepared by mixing hydrofluoric acid and hydrogen peroxide, and the ratio of hydrofluoric acid to hydrogen peroxide is 1:2.

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