Furnace tube structure for TOPCon battery and use method of furnace tube structure

Abstract

The invention discloses a furnace tube structure for a TOPCon battery and a using method thereof.The furnace tube structure comprises a closed tube body, a gas inlet tube and a gas outlet tube, the structural design that gas enters the bottom of the closed tube body uniformly and gas exits the top of the closed tube body uniformly is adopted, and the problems that a conventional low-pressure diffusion furnace tube is unstable in flow field, unstable in furnace tube head and tail square resistance control and poor in stability can be avoided. Air flow passes through a silicon wafer and can fully immerse the silicon wafer, an impurity source carried by the air flow can fully make contact with the silicon wafer and is evenly attached to the surface of the silicon wafer, meanwhile, the direction of the air flow is parallel to the silicon wafer, and therefore the silicon wafer can be fully immersed in the air flow. The air flow form cannot be disturbed due to the arrangement mode of the silicon wafers, meanwhile, the structural design can avoid the flow field fluctuation problem, the air flow of the air inlet pipe can be controlled to carry out heat regulation and control, temperature saturation is achieved, and good uniformity and stability are achieved in the whole follow-up technological process.

Description

Technical Field

[0001] The invention belongs to the technical field of photovoltaics, and in particular relates to a furnace tube structure for a TOPCon battery and a use method thereof. Background Art

[0002] At present, thermal diffusion furnaces are often used in the industrial production of TOPCon (tunneling oxide passivation contact) solar cells. Thermal diffusion furnaces are currently divided into head-intake thermal diffusion furnaces and tail-intake thermal diffusion furnaces.

[0003] No matter it is a thermal diffusion furnace with head air intake or tail air intake, the gas flow path is too long. The gas is easily affected by the unstable temperature field when flowing in the tube, which makes the air flow turbulent and forms undesirable gas flow forms such as turbulence and turbulence, resulting in poor gas uniformity in the furnace. During the diffusion process, the poor gas distribution uniformity leads to poor impurity distribution, which ultimately leads to poor resistance uniformity after silicon wafer diffusion. At the same time, there is only one tube for improving air intake and exhaust. If blockage occurs during long-term process processing, it will seriously affect the process quality.

[0004] Also, because the air flow rate at the air inlet end of this structure is large, it is easy to cause uneven pressure in the tube when the mechanical pump quickly pumps air to low pressure. The air inlet pressure is small and the air outlet pressure is large, which not only affects the service life of the furnace tube, but also affects the diffusion uniformity. Ultimately, the uniformity deviation between and within the silicon wafers after diffusion is large, and a uniform PN junction with excellent performance cannot be formed. Summary of the invention

[0005] In order to solve the problems raised in the above background technology, the present invention provides a furnace tube structure for TOPCon battery and a method of using the same, so as to solve the problems in the prior art that the gas flow path is too long and the pressure in the tube is uneven.

[0006] To achieve the above object, the present invention provides the following technical solutions: A furnace tube structure for a TOPCon battery, comprising: A closed tube body; a furnace door is provided on the closed tube body, a plurality of air inlets and a plurality of air outlets are respectively provided on both sides of the closed tube body, the air inlets and the air outlets are symmetrically arranged about the central axis of the closed tube body, and the silicon wafer is arranged in the closed tube body; An air inlet pipe for conveying gas into the closed tube body; the air inlet pipe is connected to all the air inlet holes; An air outlet pipe is used to output the gas in the closed tube body; the air outlet pipe is connected to all the air outlet holes.

[0007] Preferably, the closed tube body is placed horizontally, all air inlets are arranged in a horizontal straight line at the bottom of the closed tube body, all air outlets are arranged in a horizontal straight line at the top of the closed tube body, and the straight line where all the air inlets and the straight line where all the air outlets are located are parallel to the central axis of the closed tube body.

[0008] Preferably, the silicon chips in the closed tube body are arranged along the central axis of the closed tube body, and the planes where all the silicon chips are located are perpendicular to the central axis of the closed tube body.

[0009] Preferably, the furnace tube structure also includes multiple outlet branch pipes and multiple inlet branch pipes, one end of an outlet branch pipe is connected to an outlet hole, and the other end is inserted into the side wall of the outlet pipe and connected to the outlet pipe, and one end of an inlet branch pipe is connected to an inlet hole, and the other end is inserted into the side wall of the inlet pipe and connected to the inlet pipe.

[0010] A method for using a furnace tube structure for a TOPCon battery comprises the following steps: S1: The silicon wafers to be processed are loaded into a quartz boat. The closed tube body adopts a low-pressure diffusion method. The quartz boat is pushed through the furnace door into the closed tube body with an internal temperature of 800-850°C. In the closed tube body, the silicon wafers to be processed are arranged along the central axis of the closed tube body, and the planes where all silicon wafers are located are perpendicular to the central axis of the closed tube body; S2: introducing 50-300 sccm of BCl3 gas, 2000-4000 sccm of N2 gas and 100-1000 sccm of O2 gas into the closed tube body through a plurality of gas inlet holes connected to the gas inlet pipe to perform a deposition operation; S3: raising the temperature of the closed tube body to 850-900° C., and continuously introducing 50-300 sccm of BCl3 gas, 2000-4000 sccm of N2 gas, and 100-1000 sccm of O2 gas into the closed tube body through a plurality of gas inlet holes connected to the gas inlet pipe, to perform a diffusion deposition operation; S4: raising the temperature of the closed tube body to 950-1050° C., introducing 2000-4000 sccm of O2 gas into the closed tube body through a plurality of air inlet holes connected to the air inlet pipe, and performing an oxidation operation on the silicon wafer; S5: Cooling the closed tube body to 800-850°C, and introducing N2 gas into the closed tube body through a plurality of air inlet holes connected to the air inlet pipe to perform a vacuum breaking operation; S6: When the temperature inside the closed tube drops to 700-800°C, take the quartz boat out of the closed tube; S7: Take the silicon wafer off the quartz boat.

[0011] Preferably, in S1, the internal temperature of the closed tube is 800°C.

[0012] Preferably, in S2, the BCl3 gas introduction amount is 300 sccm, the N2 gas introduction amount is 3000 sccm, and the O2 gas introduction amount is 1000 sccm.

[0013] Preferably, in S3, the temperature of the sealed tube is raised to 850°C, the BCl3 gas flow rate is 200 sccm, the N2 gas flow rate is 4000 sccm, and the O2 gas flow rate is 600 sccm.

[0014] Preferably, in S4, the temperature of the sealed tube is raised to 1045° C., and the amount of O 2 gas introduced is 17000 sccm.

[0015] Preferably, in S5, the amount of N2 gas introduced when breaking the vacuum is 18000 sccm.

[0016] Compared with the prior art, the present invention has the following beneficial effects: The air intake and exhaust method of the present application is inconsistent with the air intake and exhaust method of the furnace tubes used in the current production line. The present application adopts a structural design of uniform air intake at the bottom of the closed tube body and uniform air outlet at the top of the closed tube body. This structural design can completely avoid the problems of unstable flow field, unstable square resistance control at the head and tail of the furnace tube, unsatisfactory uniformity, and other problems caused by structural design defects, such as uneven square resistance and large process fluctuations.

[0017] In the present application, the airflow path is greatly shortened and is fully controllable. The airflow path runs from the bottom of the closed tube body to the top of the closed tube body, passing through the silicon wafer on the way, and can fully immerse the silicon wafer. The impurity source carried in the airflow can fully contact the silicon wafer and evenly adhere to the surface of the silicon wafer. The airflow pattern will not be disturbed by the arrangement of the silicon wafer, thereby ensuring that the airflow pattern is stable from the air inlet to the air outlet.

[0018] At the same time, this structural design can avoid the problem of flow field fluctuations. When the furnace door is closed and vacuum is started, the temperature rises and the air flow in the air inlet pipe can be controlled to regulate heat and achieve temperature saturation, thereby achieving good uniformity and stability in the entire subsequent process. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the structure of the furnace tube for TOPCon batteries.

[0020] The markings in the figure are: 1-closed tube body; 2-silicon wafer; 3-inlet branch pipe; 4-inlet pipe; 5-outlet pipe; 6-outlet branch pipe. DETAILED DESCRIPTION

[0021] In order to facilitate those skilled in the art to understand the technical content of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific examples. It should be understood that the specific examples described herein are only used to explain the present invention and are not used to limit the present invention.

[0022] like Figure 1 As shown, a furnace tube structure for a TOPCon battery includes: A closed tube body 1; a furnace door is provided on the closed tube body 1, and a plurality of air inlets and a plurality of air outlets are respectively provided on both sides of the closed tube body 1, the air inlets and the air outlets are symmetrically arranged about the central axis of the closed tube body 1, and the silicon wafers 2 are arranged in the closed tube body 1, and the silicon wafers 2 in the closed tube body 1 are arranged along the central axis of the closed tube body 1, and the planes where all the silicon wafers 2 are located are perpendicular to the central axis of the closed tube body 1; An air inlet pipe 4 for conveying gas into the closed tube body 1; the air inlet pipe 4 is connected to all the air inlet holes; An outlet pipe 5 is used to output the gas in the closed tube body 1; the outlet pipe 5 is connected to all the outlet holes, the closed tube body 1 is placed horizontally, all the air inlet holes and all the air outlet holes are arranged in a horizontal straight line at the bottom and top of the closed tube body 1 respectively, and the straight line where all the air inlet holes are located and the straight line where all the air outlet holes are located are parallel to the central axis of the closed tube body 1.

[0023] Multiple outlet branch pipes 6 and multiple inlet branch pipes 3; one end of an outlet branch pipe 6 is connected to an outlet hole, and the other end is inserted into the side wall of the outlet pipe 5 and connected to the outlet pipe 5; one end of an inlet branch pipe 3 is connected to an inlet hole, and the other end is inserted into the side wall of the inlet pipe 4 and connected to the inlet pipe 4.

[0024] A method for using a furnace tube structure for a TOPCon battery comprises the following steps: S1: The silicon wafers 2 to be processed are loaded into a quartz boat. The closed tube body 1 adopts a low-pressure diffusion method. The quartz boat is pushed through the furnace door into the closed tube body 1 with an internal temperature of 800°C. In the closed tube body 1, the silicon wafers 2 to be processed are arranged along the central axis of the closed tube body 1, and the planes where all the silicon wafers 2 are located are perpendicular to the central axis of the closed tube body 1; S2: 300 sccm of BCl3 gas, 3000 sccm of N2 gas and 1000 sccm of O2 gas are introduced into the closed tube body 1 through a plurality of gas inlet holes connected to the gas inlet pipe 4 to perform a deposition operation; S3: raising the temperature of the closed tube body 1 to 850° C., and continuing to introduce 200 sccm of BCl3 gas, 4000 sccm of N2 gas, and 600 sccm of O2 gas into the closed tube body 1 through a plurality of gas inlet holes connected to the gas inlet pipe 4, to perform a diffusion deposition operation; S4: raising the temperature of the closed tube body 1 to 1045° C., introducing 17000 sccm of O2 gas into the closed tube body 1 through a plurality of air inlet holes connected to the air inlet pipe 4, and performing an oxidation operation on the silicon wafer 2; S5: Cooling the closed tube body 1 to 800° C. and introducing 18000 sccm of N2 gas into the closed tube body 1 through a plurality of gas inlet holes connected to the gas inlet pipe 4 to perform a vacuum breaking operation; S6: When the temperature in the closed tube body 1 drops to 800° C., the quartz boat is taken out of the closed tube body 1; S7: Take the silicon wafer 2 off the quartz boat.

[0025] The air intake and exhaust method of the present application is inconsistent with the air intake and exhaust method of the furnace tube used in the current production line. The present application adopts a structural design in which the air is evenly inlet at the bottom of the closed tube body 1 and the air is evenly exhausted at the top of the closed tube body 1. This structural design can completely avoid the problems of unstable flow field, unstable square resistance control at the head and tail of the furnace tube, unsatisfactory uniformity, and other problems caused by structural design defects, such as uneven square resistance and large process fluctuations.

[0026] In this application, if Figure 1 As shown in the figure, the arrow is the direction of airflow, the airflow path is greatly shortened, the airflow path is fully controllable, the airflow path is from the bottom of the closed tube body 1 to the top of the closed tube body 1, passing through the silicon wafer 2 on the way, and can fully immerse the silicon wafer 2. The impurity source carried in the airflow can fully contact the silicon wafer 2 and evenly adhere to the surface of the silicon wafer 2. At the same time, the airflow direction is parallel to the silicon wafer 2, and the airflow pattern will not be disturbed by the arrangement of the silicon wafer 2, ensuring that the airflow pattern is stable from the air inlet to the air outlet.

[0027] At the same time, this structural design can avoid the problem of flow field fluctuations. When the furnace door is closed and vacuum is started, the temperature rises and the air flow rate of the air inlet pipe 4 can be controlled to perform heat regulation to achieve temperature saturation and achieve good uniformity and stability in the subsequent entire process.

Claims

1. A furnace tube structure for a TOPCon battery, characterized in that: include: A closed tube body (1); a furnace door is provided on the closed tube body (1); a plurality of air inlet holes and a plurality of air outlet holes are respectively provided on both sides of the closed tube body (1); the air inlet holes and the air outlet holes are symmetrically arranged about the central axis of the closed tube body (1); and a silicon wafer (2) is arranged in the closed tube body (1); An air inlet pipe (4) for conveying gas into the closed tube body (1); the air inlet pipe (4) is connected to all the air inlet holes; An air outlet pipe (5) is used for outputting the gas in the closed tube body (1); the air outlet pipe (5) is connected to all the air outlet holes.

2. A furnace tube structure for TOPCon battery according to claim 1, characterized in that: The closed tube body (1) is placed horizontally, all the air inlet holes are arranged in a horizontal straight line at the bottom end of the closed tube body (1), and all the air outlet holes are arranged in a horizontal straight line at the top end of the closed tube body (1), and the straight line on which all the air inlet holes are located and the straight line on which all the air outlet holes are located are parallel to the central axis of the closed tube body (1).

3. A furnace tube structure for TOPCon battery according to claim 1, characterized in that: The silicon wafers (2) in the closed tube body (1) are arranged along the central axis of the closed tube body (1), and the planes on which all the silicon wafers (2) are located are perpendicular to the central axis of the closed tube body (1).

4. A furnace tube structure for TOPCon battery according to claim 1, characterized in that: The furnace tube structure further comprises a plurality of outlet branch pipes (6) and a plurality of inlet branch pipes (3), one end of an outlet branch pipe (6) being connected to an outlet hole, the other end of which is inserted into the side wall of the outlet pipe (5) and connected to the outlet pipe (5), and one end of an inlet branch pipe (3) being connected to an inlet hole, the other end of which is inserted into the side wall of the inlet pipe (4) and connected to the inlet pipe (4).

5. A method for using a furnace tube structure for a TOPCon battery, applied to a furnace tube structure for a TOPCon battery as claimed in any one of claims 1 to 4, characterized in that: The following steps are involved: S1: The silicon wafers (2) to be processed are loaded into a quartz boat. The closed tube (1) adopts a low-pressure diffusion method, and the quartz boat is pushed through the furnace door into the closed tube (1) with an internal temperature of 800-850° C. In the closed tube (1), the silicon wafers (2) to be processed are arranged along the central axis of the closed tube (1), and the planes where all the silicon wafers (2) are located are perpendicular to the central axis of the closed tube (1); S2: introducing 50-300 sccm of BCl3 gas, 2000-4000 sccm of N2 gas and 100-1000 sccm of O2 gas into the closed tube body (1) through a plurality of gas inlet holes connected to the gas inlet pipe (4) to perform a deposition operation; S3: raising the temperature of the closed tube body (1) to 850-900° C., and continuing to introduce 50-300 sccm of BCl 3 gas, 2000-4000 sccm of N 2 gas, and 100-1000 sccm of O 2 gas into the closed tube body (1) through a plurality of gas inlet holes connected to the gas inlet pipe (4), to perform a diffusion deposition operation; S4: raising the temperature of the closed tube body (1) to 950-1050° C., introducing 2000-4000 sccm of O2 gas into the closed tube body (1) through a plurality of air inlet holes connected to the air inlet pipe (4), and performing an oxidation operation on the silicon wafer (2); S5: cooling the closed tube body (1) to 800-850° C., and introducing N 2 gas into the closed tube body (1) through a plurality of air inlet holes connected to the air inlet pipe (4) to perform a vacuum breaking operation; S6: When the temperature in the closed tube body (1) drops to 700-800° C., the quartz boat is taken out of the closed tube body (1); S7: Remove the silicon wafer (2) from the quartz boat.

6. The method for using a furnace tube structure for a TOPCon battery according to claim 5, characterized in that: In S1, the internal temperature of the closed tube (1) is 800°C.

7. The method for using a furnace tube structure for a TOPCon battery according to claim 5, characterized in that: In S2, the BCl3 gas flow rate is 300 sccm, the N2 gas flow rate is 3000 sccm, and the O2 gas flow rate is 1000 sccm.

8. The method for using a furnace tube structure for a TOPCon battery according to claim 5, characterized in that: In S3, the temperature of the closed tube (1) is raised to 850°C, the amount of BCl3 gas introduced is 200 sccm, the amount of N2 gas introduced is 4000 sccm, and the amount of O2 gas introduced is 600 sccm.

9. The method for using a furnace tube structure for a TOPCon battery according to claim 5, characterized in that: In S4, the temperature of the closed tube (1) is raised to 1045°C, and the amount of O2 gas introduced is 17000 sccm.

10. The method for using a furnace tube structure for a TOPCon battery according to claim 5, characterized in that: In S5, the amount of N2 gas introduced when breaking the vacuum is 18000 sccm.

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