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CN-122003113-A - Method for prolonging service life of boron-expanded quartz device

CN122003113ACN 122003113 ACN122003113 ACN 122003113ACN-122003113-A

Abstract

The invention belongs to the technical field of battery manufacturing, and particularly relates to a method for prolonging the service life of a boron-expanded quartz device, which comprises the steps of S1, preprocessing, carrying out RCA standard cleaning on a silicon wafer, S2, preprocessing a wafer loading and furnace tube, loading the cleaned silicon wafer into a quartz boat, sending the quartz boat into a tubular diffusion furnace, carrying out nitrogen purging to remove residual air in the furnace tube, S3, heating, closing the tube, detecting the leak of the tube, stabilizing the tube, detecting the tightness of the furnace tube in a nitrogen pressure maintaining mode, S4, pre-oxidizing, forming a thin oxide film layer on the surface of the silicon wafer, S5, depositing a boron source, S6, carrying out propulsion, S7, carrying out post-oxidizing, preparing a BSG layer, S8, carrying out back pressure purging and cooling, and S9, taking the wafer. The invention can be far away from the softening temperature of quartz materials by reducing the core oxidation temperature from 1040 ℃ to below 1000 ℃, so that the softening deformation of devices such as quartz furnace tubes, quartz boats and the like is obviously reduced, the service life of the devices is prolonged, and the cost of accessory replacement and production line shutdown is reduced.

Inventors

  • YANG HAO
  • LIU BING

Assignees

  • 弘元新材料(徐州)有限公司
  • 弘元绿色能源股份有限公司

Dates

Publication Date
20260508
Application Date
20251222

Claims (10)

  1. 1. A method for extending the lifetime of a boron-expanded quartz device comprising the steps of: s1, preprocessing, and performing RCA standard cleaning on a silicon wafer; s2, pretreating a wafer and a furnace tube, loading the cleaned silicon wafer to a quartz boat and sending the quartz boat to a tube type diffusion furnace, and purging nitrogen to remove residual air in the furnace tube; S3, heating, closing the tube, detecting leakage, and detecting the tightness of the furnace tube in a nitrogen pressure maintaining mode after the tube is stable; s4, pre-oxidizing to form an oxide film layer on the surface of the silicon wafer; s5, depositing a boron source; S6, propulsion treatment; S7, post-oxidizing to prepare a BSG layer; S8, back pressure purging and cooling; s9, taking tablets.
  2. 2. The method for prolonging the service life of the boron-expanded quartz device according to claim 1, wherein S2 comprises: s21, loading a silicon wafer, namely loading the silicon wafer to a quartz boat with the right side facing upwards; S22, furnace tube pretreatment, namely, conveying the quartz boat into an effective reaction zone of the furnace tube, centering and aligning, closing a furnace door, and then introducing nitrogen for purging.
  3. 3. The method for prolonging the service life of the boron-expanded quartz device according to claim 2, wherein the step S3 specifically comprises the following steps: S31, heating control, wherein nitrogen is introduced in the heating process to maintain the pressure in the furnace to be 150mbar; s32, stabilizing the temperature to 825 ℃ and then keeping the temperature for 30S, so as to ensure the uniformity of the temperature field in the furnace tube; s33, closing the pipe and detecting leakage.
  4. 4. The method for prolonging the service life of the boron-expanded quartz device according to claim 3, wherein S4 specifically comprises the following steps: S41, atmosphere configuration, namely regulating the pressure in the furnace to 170mbar, controlling the flow ratio of oxygen to nitrogen to be 1:5 through a gas mixer, and mixing for 30 seconds to ensure uniform gas; s42, pre-oxidizing treatment, namely maintaining 825 ℃ and 170mbar pressure and the atmosphere, and treating for 300 seconds to form an oxide film with the thickness of 5-8nm on the surface of the silicon wafer.
  5. 5. The method for prolonging the service life of the boron-expanded quartz device according to claim 4, wherein S5 adopts progressive flow control, and specifically comprises the following steps: S51, depositing a low-concentration boron source, maintaining the temperature of the furnace at 825 ℃ and the pressure at 170mbar, introducing oxygen at 400sccm and nitrogen at 1700sccm, stabilizing for 30 seconds, introducing boron trichloride, and depositing for 180 seconds; s52, depositing a medium-concentration boron source, heating to 835 ℃ at a rate of 3 ℃ per minute, stabilizing for 20S, keeping the gas flow unchanged, and depositing for 180S; And S53, depositing a high-concentration boron source, heating to 845 ℃ at a speed of 3 ℃ per minute, stabilizing for 20S, maintaining the gas environment, and depositing for 180S to ensure that the penetration depth of boron atoms reaches 50-60nm, thereby forming a PN junction.
  6. 6. The method for prolonging the service life of the boron-expanded quartz device according to claim 5, wherein the step S6 specifically comprises the following steps: s61, atmosphere switching, namely closing a boron source channel and switching into pure nitrogen reducing atmosphere; s62, heating to 900 ℃ at the speed of 4 ℃ per min, stabilizing for 30S, and maintaining the pressure in the furnace to be 170mbar and the flow of nitrogen to be stable; And S63, performing propulsion treatment, maintaining the temperature of 900 ℃ and the pressure of 170mbar, and performing treatment for 750 seconds to ensure that the depth of the PN junction reaches 80-100nm.
  7. 7. The method for prolonging the service life of the boron-expanded quartz device according to claim 6, wherein the step S7 specifically comprises the following steps: s71, atmosphere switching, namely closing a nitrogen channel and switching high-purity oxygen; S72, heating to 1000 ℃ at a speed of 5 ℃ per min and stabilizing for 30S, and synchronously lifting the oxygen flow to 28000sccm and the pressure in the furnace to 900mbar; and S73, performing post-oxidation treatment, namely maintaining the temperature, the pressure and the oxygen flow, and performing treatment for 4800S.
  8. 8. The method for prolonging the service life of the boron-expanded quartz device according to claim 7, wherein S8 comprises the following steps: S81, back pressure control, stopping heating, keeping the oxygen flow at 28000sccm, and gradually reducing the pressure to normal pressure; s82, nitrogen purging, namely switching to nitrogen supply, and purging for 300 seconds to remove residual gas; S83, cooling treatment, namely continuously introducing nitrogen to maintain micro-positive pressure in the furnace, and naturally cooling to below 300 ℃.
  9. 9. The method for prolonging the service life of a boron-expanded quartz device according to claim 4, wherein S5 is controlled by pulse gas supply, the tubular diffusion furnace is provided with a pulse gas supply controller, and the step S5 specifically comprises the following steps: S51, temperature control, namely heating to 840 ℃ at the speed of 3 ℃ per minute and stabilizing for 20S to ensure uniform temperature in the furnace; S52, pulse parameter setting, namely starting a pulse air supply controller, setting a pulse frequency of 0.5Hz, wherein each pulse period comprises 12 seconds of air supply time and 6 seconds of interval time; And S53, pulse gas supply deposition, introducing oxygen, nitrogen and high-purity boron trichloride, maintaining the furnace pressure at 170mbar, and depositing for 540S to form a uniform boron-rich layer.
  10. 10. The method for prolonging the service life of the boron-expanded quartz device according to claim 7, wherein the step S6 specifically comprises the following steps: s61, atmosphere switching, namely closing a boron source channel and switching into pure nitrogen reducing atmosphere; s62, heating to 900 ℃ at the speed of 4 ℃ per min, stabilizing for 30S, and maintaining the pressure in the furnace to be 170mbar and the flow of nitrogen to be stable; and S63, adjusting the pulse air supply frequency to 0.2Hz, wherein each pulse period comprises 15 seconds of air supply time and 10 seconds of interval time.

Description

Method for prolonging service life of boron-expanded quartz device Technical Field The invention belongs to the technical field of battery manufacturing, and particularly relates to a method for prolonging the service life of a boron-expanded quartz device. Background The photovoltaic energy is taken as a core component of clean and renewable energy, plays a key role in global energy structure transformation, TOPCO batteries become one of the main technologies in the current photovoltaic battery field by virtue of the advantages of high conversion efficiency, long service life and the like, in the preparation process of the TOPCO batteries, the boron diffusion process is a core process for forming PN junctions, the core aim is to realize uniform doping of boron atoms on the surface of N-type silicon wafers and prepare boron doped silicon oxide layers (BSG layers) with the thickness of more than or equal to 90nm, and the BSG layers are required to effectively protect the front boron doped layers from being corroded in the subsequent RCA edge-winding plating process, so that the electrical performance and the structural stability of the batteries are directly influenced; However, the existing boron diffusion process has core technical pain points, and the stability of the production line and the control of the production cost are severely restricted: The quartz device has the advantages of quick loss and high production line maintenance cost, and the traditional boron diffusion process is used for meeting the preparation requirement of a BSG layer with the wavelength of more than 90nm, and a large amount of 28000sccm of oxygen is introduced under the high-temperature environment of 1040 ℃ and the reaction time of 4200s is maintained. The temperature is close to the softening temperature of a quartz material, the quartz device is irreversibly softened and deformed due to the continuous high-temperature environment, the uniformity of an airflow field in a furnace is damaged due to deformation of a quartz furnace tube, the uniformity of boron diffusion is reduced, the silicon wafer is easy to be blocked and damaged in the process of loading and unloading a wafer due to deformation of a quartz boat, the yield of products is reduced, the deformed quartz device needs to be frequently replaced, the purchase cost of accessories is increased, the downtime of a production line is prolonged, and the production efficiency is limited; Therefore, the development of the boron diffusion process method capable of reducing the loss of the quartz device has important industrial application value and technical innovation significance. Disclosure of Invention The invention aims to provide a method for prolonging the service life of a boron-expanded quartz device, which can reduce the core oxidation temperature from 1040 ℃ to below 1000 ℃, keep away from the softening temperature of quartz materials, obviously reduce the softening deformation of devices such as quartz furnace tubes, quartz boats and the like, prolong the service life of the devices, reduce the cost of fitting replacement and production line shutdown, and simultaneously ensure that boron atoms are uniformly doped and the thickness of a BSG layer is more than or equal to 90nm through progressive flow control sectional switching, and ensure that the electrical property and the structural stability of a battery are not lower than those of the traditional process. The technical scheme adopted by the invention is as follows: A method for extending the lifetime of a boron-expanded quartz device comprising the steps of: s1, preprocessing, and performing RCA standard cleaning on a silicon wafer; s2, pretreating a wafer and a furnace tube, loading the cleaned silicon wafer to a quartz boat and sending the quartz boat to a tube type diffusion furnace, and purging nitrogen to remove residual air in the furnace tube; S3, heating, closing the tube, detecting leakage, and detecting the tightness of the furnace tube in a nitrogen pressure maintaining mode after the tube is stable; S4, pre-oxidizing to form a thin oxide film layer on the surface of the silicon wafer; s5, depositing a boron source; S6, propulsion treatment; S7, post-oxidizing to prepare a BSG layer; S8, back pressure purging and cooling; s9, taking tablets. The step S2 comprises the following steps: s21, loading a silicon wafer, namely loading the silicon wafer to a quartz boat with the right side facing upwards; S22, furnace tube pretreatment, namely, conveying the quartz boat into an effective reaction zone of the furnace tube, centering and aligning, closing a furnace door, and then introducing nitrogen for purging. The step S3 specifically comprises the following steps: S31, heating control, wherein nitrogen is introduced in the heating process to maintain the pressure in the furnace to be 150mbar; s32, stabilizing the temperature to 825 ℃ and then keeping the temperature for 30S, so as to ensure the uniformity