Trichlorosilane conveying equipment
By designing a trichlorosilicon delivery device containing a CEM evaporator, combined with high-precision flow control and PLC control system, the problem of unstable trichlorosilicon carrying amount during pressure and temperature changes in traditional foaming equipment is solved, and efficient and stable epitaxial growth is achieved.
Patent Information
- Application Number
- CN202411590190.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-08
- Publication Date
- 2025-03-25
AI Technical Summary
During the epitaxial growth process, traditional trichlorosilane foaming equipment leads to unstable carrying amount of trichlorosilane, slow growth rate of epitaxial layer, low accuracy, and poor long-term stability.
Design a trichlorosilicon delivery device including a CEM evaporator, and realizes efficient mixing and evaporation of trichlorosilicon and hydrogen through TCS liquid inlet pipeline, carrier gas inlet pipeline, process gas outlet pipeline, sewage discharge pipeline and purge pipeline, combined with a high-precision flow controller and PLC control system.
The equipment can stably control the concentration and flow rate of trichlorosilicon under small changes in pressure and temperature, improve epitaxial growth rate and accuracy, and enhance the stability and safety of the system.
Smart Images
Figure CN119687386A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the field of high-purity gas-liquid mixing and relates to trichlorosilane conveying equipment. Background Art
[0002] Growing a single crystal thin film on a single crystal polished wafer is called an epitaxial silicon wafer. Generally, epitaxial growth is performed on the wafer by chemical vapor deposition. First, the wafer is transferred to the base of the epitaxial reaction chamber to support the wafer. Then the epitaxial reaction chamber is heated up. After reaching the preset temperature, a clean gas (such as hydrogen) is introduced to remove the natural oxide on the surface of the wafer. Then, silicon source gas is introduced to continuously and evenly grow the epitaxial layer on the front of the wafer. The thickness and resistivity of the epitaxial layer are crucial to the back-end process.
[0003] The silicon source gas used in the epitaxial growth process is trichlorosilane (SiHCl3), which is stored in liquid form at room temperature. At present, hydrogen is often used in epitaxial growth to carry trichlorosilane gas into the epitaxial reaction chamber through a bubbler. If the temperature in the bubbler changes or the pressure of the hydrogen carrier gas fluctuates, the amount of TCS carried may change; if the pressure or temperature of the outlet pipeline of the bubbler fluctuates, micro-condensation of TCS may occur; ultimately, the quality of the epitaxial silicon wafers cannot meet customer requirements, and the solubility of TCS in the hydrogen carrier gas remains unchanged under the condition of constant temperature and pressure in the traditional foaming method, so the growth rate of the epitaxial layer of this method is limited. In summary, the epitaxial growth of traditional foaming equipment is very slow, the absolute precision is low, and the long-term stability is poor.
[0004] Therefore, a trichlorosilane conveying device is designed to overcome the above problems. Summary of the invention
[0005] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a trichlorosilane conveying device with simple and reasonable structure, efficient and stable operation, high precision, wide concentration control range, low cost, and safe and reliable system.
[0006] The present invention is realized by the following technical scheme: a trichlorosilane conveying device, which comprises at least one CEM evaporator, wherein the CEM evaporator is connected with a TCS liquid inlet pipeline, a carrier gas inlet pipeline, a process gas outlet pipeline, a sewage pipeline and a purge pipeline, wherein the TCS liquid inlet pipeline is connected with a TCS stock liquid tank, a trichlorosilane solution is stored in the TCS stock liquid tank, the liquid is poured into the CEM evaporator through the TCS liquid inlet pipeline, the carrier gas inlet pipeline is connected with an external hydrogen tank, the purge pipeline is connected with a purge tank, high-purity nitrogen is placed in the purge tank as purge gas, and a valve control switch is installed on each pipeline, when the CEM evaporator is working, the valves of the TCS liquid inlet pipeline, the carrier gas inlet pipeline and the process gas outlet pipeline are opened, and the valves of the purge pipeline and the sewage pipeline are closed, when the cleaning work is in progress, the valves of the purge pipeline and the sewage pipeline are opened, and the valves of the TCS liquid inlet pipeline, the carrier gas inlet pipeline and the process gas outlet pipeline are closed.
[0007] Preferably, the sewage pipe is a vacuum pipe, and there are three of them, which are respectively installed at the front end of the CEM evaporator, below the CEM evaporator, and at the rear end of the CEM evaporator. A valve is provided on each pipe, and a negative pressure pipe is also provided on the sewage pipe near the outlet, so that excess gas or liquid can be discharged through negative pressure. The gas used in the negative pressure pipe and the sewage pipe is nitrogen.
[0008] Preferably, flow controllers and valves are installed on the TCS liquid inlet pipeline and the carrier gas inlet pipeline, and the ratio of liquid inlet to gas inlet is achieved through the flow controllers and valves.
[0009] Preferably, the flow controller and the valve are both controlled by a PLC control system.
[0010] A method for using a trichlorosilane delivery device, the method comprising the following steps: 1) Clean the equipment first, open the valves on the purge pipe and the drain pipe, close the valves on the TCS liquid inlet pipe and the carrier gas inlet pipe, and purge and drain the inside of the equipment; 2) After cleaning, close the purge pipe and the sewage pipe, set the corresponding valve parameters on the PLC control system, and then open the valve on the TCS liquid inlet pipe and the carrier gas inlet pipe valve to let the trichlorosilane liquid and hydrogen carrier gas enter the CEM evaporator respectively, and then let the mixed gas of trichlorosilane and hydrogen flow out through the exhaust pipe; 3) When the output is reached, close the TCS liquid inlet pipeline and the carrier gas inlet pipeline, open the valve on the purge pipeline and the valve on the sewage pipeline again, and purge and drain the equipment in the entire equipment pipe; 4) After the sewage is discharged, repeat steps 2 and 3 again.
[0011] As a preferred embodiment, the specific method of purging and draining in step 1 and step 3 is: 1) Close the TCS liquid inlet pipeline, carrier gas inlet pipeline, and process gas outlet pipeline. After they are completely closed, open the purge pipeline, which is arranged at the front end, middle section, and tail end of the CEM evaporator, respectively. It can purge out the liquid at the front end, the gas-liquid mixture in the middle, and the vapor mixture at the tail, respectively. Introduce nitrogen into the purge pipeline to blow and suck out the waste gas and waste liquid in these pipelines. Finally, use the negative pressure pipeline to squeeze out the residue under negative pressure to achieve the work of purging and sewage discharge.
[0012] The beneficial effects of the present invention are as follows: 1. The present invention can well solve the traditional foaming method's strict requirements on pressure and temperature. Even a small change may affect the quality of the product. The gasification method, on the other hand, has less strict requirements on pressure and temperature, and can theoretically improve the qualified rate of the product; 2. Compared with the traditional foaming method, which is relatively slow in production, the gasification method can improve the efficiency of gasification by increasing the power; 3. The present invention can accurately control the flow rate of mixed gas and the ratio of mixed gas through a high-precision flow controller.
[0013] 4. In the present invention, the supply amount of TCS liquid is controlled by LFC; the amount of carrier gas entering is controlled by MFC; these fixed amounts of liquid and carrier gas are fully mixed and evaporated to a mixed vapor state in the CEM evaporator, and then transported to the downstream machine end; this method is very simple and can produce any concentration of evaporated gas within a few seconds with high accuracy and stability; the supply amount of TCS can be adjusted to increase the epitaxial growth rate; and the concentrations of TCS and carrier gas are adjustable. BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Figure 1 It is a schematic diagram of the overall structure of the present invention. DETAILED DESCRIPTION
[0015] In order to enable those skilled in the art to more clearly understand the objectives, technical solutions and advantages of the present invention, the present invention is further described below in conjunction with the accompanying drawings and embodiments.
[0016] In the description of the present invention, it is necessary to understand that the orientation or position relationship indicated by the terms such as "up", "down", "left", "right", "inside", "outside", "horizontal" and "vertical" is based on the orientation or position relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention, rather than indicating or implying that the device or original referred to must have a specific orientation, and therefore cannot be understood as a limitation on the present invention.
[0017] The present invention will be described in detail below with reference to the accompanying drawings: Figure 1 As shown, a trichlorosilane delivery device comprises at least one CEM evaporator 1, the CEM evaporator 1 is connected with a TCS liquid inlet pipeline 2, a carrier gas inlet pipeline 3, a process gas outlet pipeline 4, a sewage pipeline 5, and a purge pipeline 6, wherein the TCS liquid inlet pipeline 2 is connected to a TCS stock liquid tank 7, the TCS stock liquid tank 7 stores trichlorosilane solution, and the liquid is poured into the CEM evaporator 1 through the TCS liquid inlet pipeline 2, and the carrier gas inlet pipeline 3 is connected to an external hydrogen tank 8 The purge pipe 6 is connected to the purge tank 9, and high-purity nitrogen is placed in the purge tank 9 as the purge gas. A valve control switch is installed on each pipe. When the CEM evaporator 1 is working, the valves of the TCS liquid inlet pipe 2, the carrier gas inlet pipe 3, and the process gas outlet pipe 4 are opened, and the valves of the purge pipe 6 and the sewage pipe 5 are closed. When cleaning, the valves of the purge pipe 6 and the sewage pipe 5 are opened, and the valves of the TCS liquid inlet pipe 2, the carrier gas inlet pipe 3, and the process gas outlet pipe 4 are closed.
[0018] The sewage pipe 5 is a vacuum pipe, and there are three of them, which are respectively installed at the front end of the CEM evaporator 1, the bottom of the CEM evaporator 1, and the rear end of the CEM evaporator 1. A valve is provided on each pipe, and a negative pressure pipe 10 is also provided on the sewage pipe 5 near the outlet, which can discharge excess gas or liquid through negative pressure. The gas used in the negative pressure pipe 10 and the sewage pipe 5 is nitrogen.
[0019] The TCS liquid inlet pipeline 2 and the carrier gas inlet pipeline 3 are both installed with a flow controller 11 and a valve, and the ratio of liquid inlet and gas inlet is achieved through the flow controller 11 and the valve.
[0020] The flow controller 11 and the valve are both controlled by a PLC control system 12 .
[0021] A method for using a trichlorosilane delivery device, the method comprising the following steps: 1) Clean the equipment first, open the valve on the purge pipe 6 and the valve on the sewage pipe 5, close the valve on the TCS liquid inlet pipe 2 and the carrier gas inlet pipe 3, and purge and drain the inside of the equipment; 2) After cleaning, close the purge pipe 6 and the sewage pipe 5, set the corresponding valve parameters on the PLC control system 12, and then open the valve on the TCS liquid inlet pipe 2 and the valve on the carrier gas inlet pipe 3 to respectively let the trichlorosilane liquid and the hydrogen carrier gas enter the CEM evaporator 1, and then let the mixed gas of trichlorosilane and hydrogen flow out through the exhaust pipe; 3) When the output is reached, close the TCS liquid inlet pipeline and the carrier gas inlet pipeline, open the valve on the purge pipeline 6 and the valve on the sewage pipeline 5 again, and purge and drain the equipment in the entire equipment pipe; 4) After the sewage is discharged, repeat steps 2 and 3 again.
[0022] The specific methods of purging and draining in step 1 and step 3 are as follows: 1) Close the TCS liquid inlet pipeline 2, the carrier gas inlet pipeline 3, and the process gas outlet pipeline 4. After they are completely closed, open the purge pipeline 6, which is arranged at the front end, the middle section, and the tail end of the CEM evaporator 1, respectively, and can purge out the liquid at the front end, the gas-liquid mixture in the middle, and the vapor mixture at the tail end, respectively. Nitrogen is introduced into the purge pipeline 6 to blow and suck out the waste gas and waste liquid in these pipelines. Finally, the negative pressure pipeline 10 is used to negatively extrude the residue to achieve the work of purging and sewage discharge.
[0023] The functional features of the components in the present invention are as follows: The valve (pressure reducing valve) at the purge tank is used to adjust the pressure of the purge gas source; TCS / DCS high-precision liquid mass flow controller, used to adjust liquid flow; The valve (pressure reducing valve) on the carrier gas inlet pipeline is used to adjust the carrier gas pressure; Flow controller (carrier gas high-precision quality) to adjust the carrier gas flow; Evaporator (mixing controller) is used to heat and evaporate liquid TCS / DCS into vapor state and fully mix it with the carrier gas; The valve (analysis test valve) on the process gas outlet pipeline is used to analyze and detect the steam concentration after the mixer; The vacuum generator is used to extract the purge exhaust gas to the outside of the equipment through the vacuum generator.
[0024] The present invention proposes to use LFC (Liquid Flowrate Control) + evaporation to supply liquid special gas. The supply of TCS liquid is controlled by LFC; the amount of carrier gas entering is controlled by MFC; these fixed amounts of liquid and carrier gas are fully mixed and evaporated to a mixed vapor state in the evaporator and transported to the downstream machine end. This method is very simple and can produce any concentration of evaporated gas within a few seconds with high accuracy and stability; the supply of TCS can be adjusted to increase the epitaxial growth rate; and the concentrations of TCS and carrier gas are adjustable.
[0025] The present invention can well solve the traditional foaming method's strict requirements on pressure and temperature, and even a slight change may affect the quality of the product. The gasification method, on the other hand, is not so strict on pressure and temperature, and in theory can improve the product's qualification rate. Compared with the traditional foaming method, which is relatively slow in production, the gasification method can improve the efficiency of gasification by increasing the power. The present invention can accurately control the flow rate of the mixed gas and the ratio of the mixed gas through a high-precision flow controller. In the present invention, the supply amount of TCS liquid is controlled by LFC; the amount of carrier gas entering is controlled by MFC; these quantitative liquids and carrier gases are fully mixed and evaporated to a mixed vapor state in the CEM evaporator, and transported to the downstream machine end; the method is very simple, and any concentration of evaporated gas can be produced within a few seconds, with high precision and stability; the supply amount of TCS can be adjusted to increase the epitaxial growth rate; and the concentrations of TCS and carrier gas are adjustable.
[0026] The specific embodiments described herein are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical ideas disclosed by the present invention shall still be covered by the claims of the present invention.
Claims
1. A trichlorosilane delivery device, comprising at least one CEM evaporator, characterized in that: The CEM evaporator is connected with a TCS liquid inlet pipeline, a carrier gas inlet pipeline, a process gas outlet pipeline, a sewage pipeline, and a purge pipeline, wherein the TCS liquid inlet pipeline is connected to a TCS stock liquid tank, trichlorosilane solution is stored in the TCS stock liquid tank, and the liquid is poured into the CEM evaporator through the TCS liquid inlet pipeline, the carrier gas inlet pipeline is connected to an external hydrogen tank, and the purge pipeline is connected to a purge tank, in which high-purity nitrogen is placed as a purge gas, and a valve control switch is installed on each pipeline. When the CEM evaporator is working, the valves of the TCS liquid inlet pipeline, the carrier gas inlet pipeline, and the process gas outlet pipeline are opened, and the valves of the purge pipeline and the sewage pipeline are closed. When cleaning work is performed, the valves of the purge pipeline and the sewage pipeline are opened, and the valves of the TCS liquid inlet pipeline, the carrier gas inlet pipeline, and the process gas outlet pipeline are closed.
2. The trichlorosilane delivery equipment according to claim 1, characterized in that: The sewage pipe is a vacuum pipe, and there are three of them, which are installed at the front end of the CEM evaporator, the bottom of the CEM evaporator, and the rear end of the CEM evaporator respectively. A valve is provided on each pipe, and a negative pressure pipe is also provided on the sewage pipe near the outlet, which can discharge excess gas or liquid through negative pressure. The gas used in the negative pressure pipe and the sewage pipe is nitrogen.
3. The trichlorosilane delivery equipment according to claim 1, characterized in that: The TCS liquid inlet pipeline and the carrier gas inlet pipeline are both equipped with flow controllers and valves, and the ratio of liquid inlet to gas inlet is achieved through the flow controllers and valves.
4. The trichlorosilane delivery equipment according to claim 3, characterized in that The flow controller and valve are both controlled by a PLC control system.
5. The method for using the trichlorosilane delivery device according to any one of claims 1 to 4, characterized in that: The method comprises the following steps: 1) Clean the equipment first, open the valves on the purge pipe and the drain pipe, close the valves on the TCS liquid inlet pipe and the carrier gas inlet pipe, and purge and drain the inside of the equipment; 2) After cleaning, close the purge pipe and the sewage pipe, set the corresponding valve parameters on the PLC control system, and then open the valve on the TCS liquid inlet pipe and the carrier gas inlet pipe valve to let the trichlorosilane liquid and hydrogen carrier gas enter the CEM evaporator respectively, and then let the mixed gas of trichlorosilane and hydrogen flow out through the exhaust pipe; 3) When the output is reached, close the TCS liquid inlet pipeline and the carrier gas inlet pipeline, open the valve on the purge pipeline and the valve on the sewage pipeline again, and purge and drain the equipment in the entire equipment pipe; 4) After the sewage is discharged, repeat steps 2 and 3 again.
6. The method for using the trichlorosilane delivery device according to claim 5, characterized in that: The specific methods of purging and draining in step 1 and step 3 are as follows: 1) Close the TCS liquid inlet pipeline, carrier gas inlet pipeline, and process gas outlet pipeline. After they are completely closed, open the purge pipeline, which is arranged at the front end, middle section, and tail end of the CEM evaporator, respectively. It can purge out the liquid at the front end, the gas-liquid mixture in the middle, and the vapor mixture at the tail, respectively. Introduce nitrogen into the purge pipeline to blow and suck out the waste gas and waste liquid in these pipelines. Finally, use the negative pressure pipeline to squeeze out the residue under negative pressure to achieve the work of purging and sewage discharge.