Precursor conveying system

Abstract

The utility model discloses a precursor delivery system which comprises at least two precursor gas sources, an inert gas source, an ultrasonic device, a first delivery pipe and a second delivery pipe, the upstream of a reactor is connected to the precursor gas sources through the second delivery pipe, and the second delivery pipe is further connected to the inert gas source through the first delivery pipe. Control valves are arranged on the second conveying pipes, gas outlet control valves are also arranged on outlets of the precursor gas sources, the ultrasonic devices are connected with the precursor gas sources and used for atomizing precursors in the precursor gas sources, the precursor gas sources are located in the first heating box to keep a first temperature, and the second conveying pipes are located in the second heating box to keep a second temperature. The second temperature is higher than the first temperature which is higher than the precursor volatilization temperature. Through the precise air supply module design and the airflow stability adjusting mechanism, the conveying flow of the precursor can be precisely controlled, the precursor source introduction stability is guaranteed, the precursor conveying efficiency is effectively improved, and the film process effect is improved.

Description

Technical Field

[0001] This utility model belongs to the field of semiconductor manufacturing, and specifically relates to a precursor delivery system. Background Technology

[0002] Atomic layer deposition (ALD) technology has wide applications in semiconductor manufacturing, nanomaterial preparation, and other fields. Its principle involves alternately pulsed introduction of a gaseous precursor into a reaction chamber, gradually forming a film on the substrate surface in a single-atom manner. In the ALD process, stable and precise precursor delivery is crucial. Currently, common precursor delivery systems face numerous problems when handling large-scale precursor delivery. For example, while increasing the carrier gas flow rate of the precursor source in existing technologies can ensure a certain delivery efficiency, it leads to drift in deposition process performance, such as reduced thickness, decreased uniformity, and decreased growth rate per cycle. Conversely, reducing the carrier gas flow rate results in low purging efficiency and fails to completely remove residual precursor sources from the piping, easily leading to chemical vapor deposition reactions, affecting the deposition step coverage, film roughness, and causing uncontrolled growth rate per cycle. In addition, for solid precursors, as the usage time increases, the supply of precursors may become insufficient, which will lead to a decrease in the deposition rate of the thin film, resulting in problems such as reduced film coverage, poor uniformity, and even reduced product yield.

[0003] In existing technologies, precursors are typically transported to the reaction chamber via carrier gas. However, fluctuations in carrier gas flow rate and time can affect the residual amount of precursor in the pipeline, leading to gas path contamination and impacting the consistency and uniformity of subsequent processes. Furthermore, when switching between different precursors, the flow control module needs to be restarted, and the restart time is much longer than the valve opening time. This causes the precursor flow rate to rise, which, when the process feed time is short, can easily result in insufficient precursor intake, leading to uneven coating.

[0004] Therefore, it is of great significance to develop an efficient, stable and precise delivery design for ALD precursors. Summary of the Invention

[0005] The purpose of this invention is to provide a precursor delivery system and method that utilizes the high-frequency vibration energy of ultrasound to atomize liquid precursors into tiny and uniform droplets. These droplets are then transported to a designated location by a carrier gas, effectively improving the precursor delivery efficiency, thereby enhancing the thin film processing effect. Furthermore, the system offers precise control, which is beneficial for controlling the composition and structure of the deposited material.

[0006] To achieve the above objectives, the technical solution of this utility model is as follows:

[0007] A precursor delivery system for delivering precursors to a reactor for processing includes at least two precursor gas sources, an inert gas source, an ultrasonic device, a first delivery pipe, and a second delivery pipe. Each precursor gas source is connected upstream of the reactor via an independent second delivery pipe, and each second delivery pipe is also connected to an inert gas source via an independent first delivery pipe. Each second delivery pipe is equipped with a control valve, and each precursor gas source outlet is also equipped with an outlet control valve. The ultrasonic device is connected to each precursor gas source for atomizing the precursors in the precursor gas sources. The precursor gas sources are located in a first heating chamber and maintained at a first temperature, while the second delivery pipes are located in a second heating chamber and maintained at a second temperature. The second temperature is greater than the first temperature, and the first temperature is greater than the precursor volatilization temperature.

[0008] The first delivery pipe is equipped with a bellows valve and a flow controller.

[0009] The inert gas source is connected to different precursor gas sources through different first delivery pipes, and each first delivery pipe is equipped with a flow controller. Therefore, after the flow controller is set with the opening degree according to the vapor ratio of different precursor gas sources, the flow controller does not need to be readjusted when switching between different precursor gas sources. This avoids the precursor from being insufficiently introduced due to the slow increase in flow rate during the flow controller opening adjustment process, resulting in uneven coating.

[0010] Different precursor gas sources are delivered to the reactor through independent second delivery pipelines. The carrier gas flow rate in each second delivery pipeline is constant and equal to the design value of the flow controller of its respective first delivery pipeline. This avoids the impact of fluctuations in carrier gas flow rate and time on the residual amount of precursor in the pipeline when switching between different precursor gas sources, which could lead to gas path contamination and affect the consistency and uniformity of subsequent processes.

[0011] Each precursor gas source is located in a first heating chamber. Each second delivery pipe is located in a second heating chamber. This allows for the setting of different first and second temperatures based on the different volatilization temperatures of the precursors.

[0012] If the precursor gas source stores volatile precursors, a single-port gas tank with only an outlet is used. The first delivery pipe is connected to the second delivery pipe between the control valve and the outlet control valve. If the precursor gas source stores non-volatile precursors, a double-port gas tank with an outlet and an inlet is used. The first delivery pipe is connected to the inlet control valve on the inlet of the precursor gas source. The second delivery pipe between the first delivery pipe and the control valve and the outlet control valve is also connected through a branch pipe with a control valve.

[0013] The first and second delivery pipes are made of stainless steel or Hastelloy, and multiple pressure sensors are installed inside the pipes.

[0014] The beneficial effects of this utility model are: (1) This utility model achieves precise control of the transport flow of the precursor through the design of the precise gas supply module and the airflow stability adjustment mechanism, ensuring the stability of the precursor source in the deposition process, effectively improving the transport efficiency of the precursor, and thus improving the process effect of the film; (2) The high-frequency vibration of the ultrasonic wave can break the precursor liquid into tiny droplets, ensuring that the precursor droplets are small and evenly distributed, so that the formed film or powder and other materials have high uniformity, which is beneficial to improving the material performance; (3) By adjusting the frequency, power and parameters of the ultrasonic wave, as well as the flow rate and temperature of the carrier gas, the size, distribution and pyrolysis reaction rate of the droplets can be precisely controlled, so as to achieve precise control of the material thickness, composition and structure; (4) The ultrasonic spray pyrolysis film-making technology can achieve high atomization efficiency, which can convert a large amount of precursor liquid into droplet vaporization in a short time, improve the transport volume of the precursor, and improve the film-making efficiency. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the conveying system structure of this utility model. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this disclosure. All other embodiments obtained by those skilled in the art based on the described embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.

[0017] like Figure 1As shown, a precursor delivery system includes a first precursor gas source 1, a second precursor gas source 2, an inert gas source 3, and an ultrasonic device 4. The first precursor gas source 1 stores non-volatile precursors and uses a dual-port gas tank with an outlet and an inlet. The inert gas source 3 is connected to the inlet control valve of the first precursor gas source 1 via a first delivery pipe 8. The outlet control valve of the first precursor gas source 1 is connected to a reactor via a second delivery pipe 10. The first delivery pipe 8 and the second delivery pipe 10 are connected via a branch pipe 11 equipped with a control valve 7d. The second precursor gas source 2 stores volatile precursors and uses a single-port gas tank with only an outlet. The gas source 3 is connected to the outlet control valve of the second precursor gas source outlet pipe 14 via another first delivery pipe 8. The outlet control valve of the first precursor gas source 2 is connected to the reactor via another second delivery pipe 10. Both the first and second precursor gas sources are equipped with ultrasonic devices 4 at their bottoms. Flow controllers 5 are installed on both first delivery pipes 8 to control the gas input. The first and second precursor gas sources 1 and 2 are respectively located in two first heating chambers 16, and the two second delivery pipes 10 are respectively located in two second heating chambers 15. The second temperature is higher than the first temperature, and the first temperature is higher than the precursor volatilization temperature. This is to prevent the sublimated precursor from condensing and crystallizing in the second delivery pipe 10. Otherwise, as the second delivery pipe 10 is used for longer periods, the inner diameter of the second delivery pipe 10 decreases due to the chemical vapor deposition reaction, leading to a decrease in flow rate and insufficient precursor supply. This results in a decrease in the film deposition rate, leading to problems such as reduced film coverage and poor uniformity, and even reduced product yield. Different first and second temperatures are set according to the different volatilization temperatures of different precursors.

[0018] Furthermore, the inert gas source 3 stores inert gas, which is a non-reactive gas at normal temperature and pressure and is difficult to undergo chemical reactions.

[0019] Furthermore, two first delivery pipes 8 are connected in series with a bellows valve 6 and a flow controller 5. The outlet of the first precursor gas source 1 is connected to a second delivery pipe 10 equipped with an outlet control valve 7b and a control valve 7f. The outlet of the second precursor gas source 2 is connected to a second delivery pipe 10 equipped with an outlet control valve 7c and a control valve 7e. The aforementioned branch pipe 11 is connected to the pipeline between the outlet control valves 7b and 7f of the second delivery pipe 10. Inert gas sources are connected to different precursor gas sources through different first delivery pipes, and each first delivery pipe is equipped with a flow controller. Therefore, after the flow controller is set with an opening degree according to the vapor ratio of different precursor gas sources, it does not need to readjust the opening degree when switching between different precursor gas sources. This avoids insufficient precursor intake and uneven coating caused by slow flow rate increase during flow controller opening adjustment.

[0020] Different precursor gas sources are delivered to the reactor through independent second delivery pipelines. The carrier gas flow rate in each second delivery pipeline is constant and equal to the design value of the flow controller of its respective first delivery pipeline. This avoids the impact of fluctuations in carrier gas flow rate and time on the residual amount of precursor in the pipeline when switching between different precursor gas sources, which could lead to gas path contamination and affect the consistency and uniformity of subsequent processes.

[0021] Furthermore, the first precursor gas source is a dual-port gas storage tank, which contains a non-volatile gas. The inert gas is introduced through the first delivery pipe 8 and mixed with the gaseous precursor in the dual-port gas storage tank, and the gaseous precursor is carried out.

[0022] Furthermore, the first and second conveying pipes are made of stainless steel or Hastelloy, which have good corrosion resistance. Multiple pressure sensors are also installed inside the conveying pipes to monitor pressure changes in the pipes in real time.

[0023] Furthermore, the ultrasonic device 4 is internally equipped with a vibrating component connected to the ultrasonic generator. Under the action of ultrasound, the ultrasonic device 4 breaks the liquid precursor in the first precursor gas source 1 and the second precursor gas source 2 into tiny droplets, ensuring that the precursor droplets are small and evenly distributed. This results in highly uniform films or powders, which is beneficial for improving material performance. The ultrasonic spray pyrolysis film-forming technology can achieve high atomization efficiency, converting a large amount of precursor liquid into droplets in a short time, avoiding insufficient precursor supply. By adjusting the frequency and power of the ultrasound, as well as the flow rate and temperature of the carrier gas, the size and distribution of the precursor droplets and the rate of the pyrolysis reaction can be precisely controlled, achieving precise control over the material thickness, composition, and structure.

[0024] As the precursors from the first precursor gas source 1 and the second precursor gas source 2 undergo a deposition reaction in the reactor, the pressure changes in the gas storage tank are monitored by a pressure sensor. When the pressure is lower than the preset pressure, ultrasonic control is performed based on the pressure data to ensure a continuous and stable supply of precursors.

[0025] The present invention also provides a precursor delivery method, comprising the following steps:

[0026] S1. Evacuate the reactor body to a vacuum, heat the reactor, open the valve of the inert gas source, adjust the nitrogen pressure reducing valve to 0.2MPa, the temperature inside the reactor reaches the set reaction temperature, control the first heating box and the second heating box to make the temperature of the second delivery pipe reach 220℃, and the temperature of the first precursor gas source 1 and the second precursor gas source 2 is heated to 200℃.

[0027] S2. Open control valve 7d and control valve 7f, set the value of the flow controller 5 of the first delivery pipe 8 connected to the first precursor gas source 1 to the powder fluidization value, and introduce nitrogen for 60 seconds to fully clean the first delivery pipe 8 and the second delivery pipe 10 connected to the first precursor gas source 1.

[0028] S3. Keep control valve 7f open, while closing control valve 7d, opening inlet control valve 7a and outlet control valve 7b, and introducing nitrogen into the first precursor gas source 1 to carry out the precursor. After holding for 5 seconds, close inlet control valve 7a and outlet control valve 7b, open control valve 7d, and clean the second delivery pipe 10 for 1200 seconds. Then close control valve 7d and control valve 7f.

[0029] S3. Open control valve 7e, set the flow controller 5 of the first delivery pipe 8 connected to the second precursor gas source 2 to the powder fluidization value, and introduce nitrogen for 60 seconds to fully clean the first delivery pipe 8 and the second delivery pipe 10 connected to the second precursor gas source 2.

[0030] S4. Keep control valve 7e open, open control valve 7c, nitrogen flows through the pipe above the second precursor gas source 2, carrying out the precursor vapor in the bottle, keep for 5 seconds and then close valve control valve 7c, and clean the second delivery pipe for 101200 seconds.

[0031] S5. Repeat steps S2-S9 until the coating is completed and then close all valves and the precursor valve.

[0032] S6. Perform pipe cleaning, specifically:

[0033] S61. When cleaning the left-side pipe, open the inlet control valve 7a, outlet control valve 7b, and control valve 7f. Manually input the value of flow controller 5 (MFC1) to 50 sccm. After introducing nitrogen for 1200 seconds, close the inlet control valve 7a, outlet control valve 7b, and control valve 7f, and change the value of flow controller 5 (MFC1) to 0.

[0034] S62. When cleaning the right-side pipe, open control valves 7c and 7e, manually input the flow controller 5 (MFC2) value to 50 sccm, introduce nitrogen gas for 1200 seconds, then close control valves 7c and 7e, and change the flow controller 5 (MFC2) value to 0.

[0035] After completing the above steps, shut off the heating of the reactor, pipeline, and precursor source bottle, and open control valves 7d, 7e, and 7f. Set the flow controller 5 (MFC1) value to 10 sccm and the flow controller 5 (MFC2) value to 10 sccm until the temperature of the reactor, pipeline, and precursor gas source drops to room temperature.

[0036] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model. Although the present utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A precursor delivery system for delivering a precursor to a reactor for processing, characterized by, The reactor comprises at least two precursor gas sources, an inert gas source, an ultrasonic device and first and second delivery pipes, wherein the reactor is connected to each precursor gas source through an independent second delivery pipe, each second delivery pipe is further connected to the inert gas source through an independent first delivery pipe, a control valve is arranged on each second delivery pipe, and an outlet control valve is arranged on the outlet of each precursor gas source, the precursor gas sources are kept at a first temperature in a first heating box, the second delivery pipes are kept at a second temperature in a second heating box, the second temperature is higher than the first temperature, and the first temperature is higher than the volatilization temperature of the precursors.

2. The delivery system of claim 1, wherein, The ultrasonic device is connected to the precursor gas sources and used for atomizing the precursors in the precursor gas sources.

3. The delivery system of claim 1, wherein, Each precursor gas source is arranged in a first heating box, and each second delivery pipe is arranged in a second heating box.

4. The delivery system of claim 1, wherein, A bellows valve and a flow controller are arranged on the first delivery pipe.

5. The delivery system of claim 1, wherein, If the precursor gas source stores volatile precursors, a single-port gas storage tank with only an outlet is used, the first delivery pipe is connected to the second delivery pipe between the control valve and the outlet control valve, if the precursor gas source stores non-volatile precursors, a double-port gas storage tank with an outlet and an inlet is used, the first delivery pipe is connected to an inlet control valve on the inlet of the precursor gas source, and the first delivery pipe and the second delivery pipe between the control valve and the outlet control valve are further connected through a branch pipe with a control valve.

6. The delivery system of claim 1, wherein, The first and second delivery pipes are made of stainless steel or hastelloy, and a plurality of pressure sensors are arranged in the pipes.

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