Solid state precursor heat trace delivery line system and method

Abstract

The application discloses a solid precursor heat tracing pipeline system and method, and relates to the technical field of semiconductor equipment manufacturing. The system comprises: a composite pipeline, which has an inner layer flow channel, an intermediate chamber and an outer layer sleeve arranged in sequence from inside to outside along a radial direction; a multi-temperature-zone heating system, which is provided with at least two independently temperature-controllable heat tracing sections along an airflow direction and controls the heating temperature to increase in sequence along the airflow direction; a local heat transfer strengthening component, which is arranged at a local position of the pipeline where the heat dissipation rate is higher than that of a straight pipe section, and is used for applying additional heat compensation or heat blocking; a displacement compensation assembly, which comprises a flexible pipe section connected in series to the inner layer flow channel and a telescopic joint arranged on the outer layer sleeve; and a leakage protection system, which fills the intermediate chamber with a protective gas to maintain a positive pressure, and determines a leakage state according to the gas pressure variation characteristics and executes a graded interlocking protection. The application solves the problems of sublimation blocking, thermal decomposition, thermal stress cracking and leakage safety during long-distance conveying of solid precursors in a semiconductor process.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor equipment manufacturing technology, and specifically relates to a solid precursor heat tracing delivery pipeline system and method. Background Technology

[0002] In the manufacturing processes of advanced integrated circuit devices such as advanced logic chips, high-density DRAM, and ultra-multilayer 3D NAND flash memory, molybdenum-containing thin film systems (including metallic molybdenum (Mo), molybdenum nitride (MoN), and molybdenum oxide (Mo)) are used. x O y Due to their excellent electrical conductivity and contact resistance characteristics, these thin films are widely used in metal interconnect layers, diffusion barrier layers, and electrode structures. These films are mainly grown using atomic layer deposition (ALD) or chemical vapor deposition (CVD) processes, with high-purity solid molybdenum dichloride (MoO2Cl2) and molybdenum pentachloride (MoCl5) as key precursors.

[0003] The aforementioned solid precursors are all solid at room temperature and have extremely low saturated vapor pressures. They typically need to be heated to 150°C to 200°C to sublimate and then transported to the process chamber in gaseous form under high vacuum or low pressure conditions. In semiconductor fabs, the transport distance from the precursor gas supply system (SDS) to the main tool is often as long as 10m to 40m due to the limitations of the physical layout of the fab.

[0004] In such long-distance gas phase transportation, conventional heat tracing pipelines have the following prominent problems.

[0005] First, localized cold spots can lead to sublimation and crystallization, as well as pipeline blockage. Solid precursors are highly susceptible to localized temperature drops during gas-phase transport. Elbows, tees, valves, and pipe clamps in pipelines, due to abrupt geometric changes or metal-solid conduction, experience significantly higher heat dissipation rates than straight pipe sections, easily creating localized low-temperature zones. If the temperature in this zone falls 1-2°C below the precursor's sublimation / condensation temperature, the gas-phase precursor will rapidly sublimate and crystallize, gradually reducing the effective pipe diameter, increasing flow resistance, and ultimately completely blocking the pipeline, causing unexpected production line shutdowns.

[0006] Secondly, there is a contradiction between heat loss along the pipe and localized overheating and decomposition. During long-distance flow, the gas temperature gradually decreases due to shear friction and adiabatic expansion. If constant-power isothermal heating is used, it cannot compensate for the heat loss along the pipe, resulting in insufficient superheat in the downstream region and a tendency for sublimation. Simply increasing the overall heating power may cause the upstream region to exceed the critical thermal decomposition temperature of the precursor (e.g., approximately 190℃ for MoO2Cl2), leading to thermal decomposition of the precursor within the pipe wall, precipitating non-volatile decomposition products, and causing fatal pipe wall fouling and particulate contamination.

[0007] Thirdly, there is the risk of stress cracking and seal failure due to high-temperature thermal expansion. During the process of a pipeline heating from room temperature to an operating temperature of 150℃~200℃, a 10m~40m long metal pipe will experience axial thermal expansion displacement of several millimeters to tens of millimeters. If this displacement cannot be flexibly absorbed, pipe bends and joints will bear enormous thermal stress, potentially leading to weld cracking or seal loosening. In high-temperature, chlorine-containing corrosive environments, conventional stainless steel also faces a serious risk of stress corrosion cracking (SCC).

[0008] Fourth, there is a lack of adequate safety protection against leaks. Molybdenum-based chloride precursors are highly chemically reactive; once leaked and exposed to atmospheric oxygen or moisture, they rapidly hydrolyze to generate highly corrosive hydrogen chloride gas and toxic acid mist, seriously threatening personnel safety and wafer products within cleanrooms. Existing piping systems lack real-time monitoring and automatic emergency response capabilities for leaks.

[0009] In the prior art, CN115928048A discloses a semiconductor device and its gas pipeline, as well as a heating method for process gases. The gas pipeline is divided into multiple sections: a first section, a second section, and a third section, sequentially connected from the gas supply source to the reaction chamber of the semiconductor processing equipment. A flow control device for the process gas is installed on the second section, and heating units are installed on the first and third sections. This zoned heating method heats the gas pipeline, preventing the process gas from depositing on the inner wall of the pipeline and preventing damage to the flow control device due to excessively high process gas temperatures. It also improves the temperature uniformity of the pipeline to some extent. However, this pipeline has a single-layer structure and lacks specific thermal compensation for areas with concentrated heat dissipation, such as bends and joints, and does not address heat displacement absorption or leakage safety protection. CN122256917A discloses a precursor delivery pipeline that alleviates condensation blockage by designing the bent pipe section with an upward-opening structure and installing a heater at the bend. However, this solution is only suitable for specific geometries and cannot meet the comprehensive requirements of ultra-long-distance delivery. CN119372628B discloses a solid precursor delivery system that adopts a segmented pressurization scheme, focusing on the gas filling control from the source bottle to the pipeline, without involving the structural optimization and safety design of the delivery pipeline itself.

[0010] In summary, there is an urgent need for a pipeline system that can systematically solve comprehensive problems such as sublimation at cold points along the pipeline, local overheating and decomposition, thermal expansion stress cracking, and leakage safety protection during ultra-long-distance transportation. Summary of the Invention

[0011] In view of the problems in the related technologies, the present invention proposes a solid precursor heat tracing delivery pipeline system and method to overcome the above-mentioned technical problems existing in the existing related technologies.

[0012] To solve the above-mentioned technical problems, the present invention is achieved through the following technical solution: A solid precursor heat tracing delivery pipeline system includes: A composite pipeline has an inner flow channel, an intermediate chamber and an outer sleeve arranged radially from the inside to the outside. The inner flow channel is connected between the gas source end and the gas consumption end of the solid precursor and is used to transport the gas phase solid precursor. A multi-temperature zone heating system is provided with at least two heat tracing sections whose heating power can be independently controlled along the airflow direction of the composite pipeline, and the heating temperature of each heat tracing section is controlled to increase sequentially along the airflow direction to compensate for the heat loss of the gaseous solid precursor during the flow process in the pipeline. A locally enhanced heat transfer component is disposed on a local part of the composite pipe where the heat dissipation rate is higher than that of the straight pipe section. It is used to apply a larger heating power per unit area and / or a smaller thermal conductivity coefficient to the local part compared to the adjacent straight pipe section, so as to suppress the temperature of the local part from being lower than that of the adjacent straight pipe section. A displacement compensation component, which is connected in series in the straight section of the composite pipeline, includes at least one flexible pipe section disposed in the inner flow channel and a telescopic joint disposed in the outer sleeve, for absorbing the thermal expansion and contraction displacement of the metal components of the composite pipeline caused by temperature changes. The leakage protection system fills the intermediate chamber with protective gas and maintains it at a positive pressure higher than the external ambient pressure. It monitors the pressure changes in the intermediate chamber through a pressure sensor and determines the leakage status of the composite pipeline based on the characteristics of the pressure changes, and executes corresponding safety interlock actions.

[0013] As a preferred technical solution, the inner flow channel is composed of a first metal tube, the intermediate chamber is composed of an annular space between a second metal tube sleeved outside the first metal tube and the outer wall of the first metal tube, and the outer sleeve is coaxially sleeved outside the second metal tube.

[0014] As a preferred technical solution, the base material of both the first metal pipe and the flexible pipe section is a high-temperature and corrosion-resistant nickel-based alloy, preferably Hastelloy C-276; the flexible pipe section is composed of at least two layers of thin-walled pipes coaxially stacked, and the single-layer wall thickness of each thin-walled pipe in the flexible pipe section is 0.15mm~0.25mm; the inner surface roughness Ra of the first metal pipe is ≤0.1μm.

[0015] As a preferred technical solution, the telescopic joint is provided with a sliding sealing structure, which includes a sealing ring that contacts the sliding friction surface and an elastomer that applies a pre-tightening force to the sealing ring; the sealing ring is made of polytetrafluoroethylene composite material containing a filler modified material, and the elastomer is made of an elastomer material with a temperature resistance of not less than 180°C.

[0016] As a preferred technical solution, the filler modification material includes carbon fiber and / or graphite; the elastomer material is perfluoroether rubber.

[0017] As a preferred technical solution, the multi-temperature zone heating system supplies heat to each of the heat-tracing sections separately through heating elements wound around or attached to the outer wall of the inner flow channel.

[0018] As a preferred technical solution, the heat tracing sections are two, three, or four; the heating temperature difference between adjacent heat tracing sections is 3℃~10℃; the heating temperature of the heat tracing section closest to the gas-using end is lower than the thermal decomposition critical temperature of the solid precursor.

[0019] As a preferred technical solution, the locally enhanced heat transfer component includes at least one of the following three: a. A non-uniform heating component disposed in the bend section of the composite pipeline provides a heating power per unit area greater in the outer region of the bend than in the inner region; preferably, the thickness of the non-uniform heating component decreases from the outer to the inner side of the bend.

[0020] b. A heating component installed at the pipe section connection joint of the composite pipeline, wherein at least one independent heating element is embedded inside, for providing the connection joint with additional heat that is higher than the heating temperature of the heat tracing section therein by a preset value; preferably, the heating component is a double-jointed structure made of metal material, wherein two symmetrically distributed independent heating elements are embedded inside, and a temperature sensor is configured for closed-loop temperature control.

[0021] c. The thermal insulation component disposed between the pipe support and the outer sleeve of the composite pipeline has a material with a lower thermal conductivity than the material of the outer sleeve. Preferably, the thermal insulation component is made of ceramic material with a thermal conductivity of less than 3 W / (m·K).

[0022] As a preferred technical solution, the leakage protection system performs graded interlocking protection actions based on the deviation between the measured air pressure value in the intermediate chamber and the theoretical reference air pressure value calculated based on the current temperature distribution, as well as the time change rate of the air pressure.

[0023] As a preferred technical solution, the hierarchical interlocking protection action includes: When the absolute value of the deviation does not exceed the first threshold, the current operating parameters remain unchanged; When the absolute value of the deviation exceeds the first threshold and the absolute value of the time change rate is within the first rate range, a minor leak is determined to have occurred, an alarm is triggered, and protective gas supply is initiated to maintain the gas pressure in the intermediate chamber at a level not lower than the safety lower limit. When the absolute value of the time change rate exceeds the second rate threshold, a serious damage or leak is determined, and emergency interlock actions are performed to cut off the precursor supply, shut down the heating power supply, and / or increase the protective gas charging flow rate, wherein the second rate threshold is greater than the upper limit of the first rate range.

[0024] As a preferred technical solution, the first threshold is 2kPa~5kPa, the first rate range is 0.05kPa / min~1.0kPa / min, and the second rate threshold is 3kPa / s~8kPa / s.

[0025] As a preferred technical solution, the theoretical reference pressure value is calculated based on the ideal gas state equation, using the initial calibration pressure and initial calibration temperature in the intermediate chamber, and the weighted average of the temperatures of each heat tracing section of the composite pipeline at the current moment.

[0026] As a preferred technical solution, the pressure value Pm of the protective gas in the intermediate chamber, the process gas pressure value Pi in the inner flow channel, and the atmospheric pressure value Po of the external environment satisfy: Pm>Po>Pi.

[0027] As a preferred technical solution, the protective gas is an inert gas or nitrogen.

[0028] As a preferred technical solution, the total length of the inner flow channel along the airflow conveying direction is 10m~40m; the process gas pressure in the inner flow channel is 1kPa~50kPa.

[0029] As a preferred technical solution, the solid precursor is a metal halide precursor or a metal oxyhalide precursor. Preferably, the solid precursor is a molybdenum-based solid precursor, including molybdenum dichlorodioxide and / or molybdenum pentachloride.

[0030] This invention also proposes a method for heat-traced transport of solid precursors, applied to the aforementioned system, comprising: Along the airflow direction, at least two heating sections of the composite pipeline are set with heating temperatures that increase sequentially along the airflow direction to compensate for the heat loss of the gaseous solid precursor during the flow process in the pipeline, so that the gaseous solid precursor is maintained in a superheated vapor state throughout the entire transportation process. A protective gas is introduced into the intermediate chamber of the composite pipeline and a positive pressure is maintained. The pressure change in the intermediate chamber is monitored by a pressure sensor. The leakage status of the composite pipeline is determined based on the pressure change characteristics, and graded safety interlocking actions are executed. The flexible pipe sections and expandable joints connected in series in the composite pipeline absorb the thermal expansion and contraction displacement of the metal components of the composite pipeline caused by temperature changes.

[0031] As a preferred technical solution, the step of determining the leakage status of the composite pipeline based on the gas pressure change characteristics and executing graded safety interlock actions includes: Obtain the measured air pressure value within the intermediate chamber; The theoretical reference pressure value is calculated based on the current weighted average temperature of each heat tracing section of the composite pipeline. When the absolute value of the deviation between the measured air pressure value and the theoretical reference air pressure value does not exceed the first threshold, the current operating state is maintained. When the absolute value of the deviation exceeds the first threshold and the rate of change of air pressure is within the first rate range, a minor leak is determined to have occurred, and air replenishment is initiated to maintain the air pressure in the intermediate chamber at a level not lower than the safety lower limit. Maintenance is then carried out after the current process is completed. When the rate of change of gas pressure exceeds the second rate threshold, a serious damage or leak is determined, and emergency interlocking actions are performed, including cutting off the supply of solid precursor, shutting off the heating power supply, and increasing the flow rate of protective gas, wherein the second rate threshold is greater than the upper limit of the first rate range.

[0032] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The three-layer nested structure of composite pipelines, combined with multi-temperature zone heating along the pipeline and local enhanced heat transfer components, ensures that the gaseous precursor is always in a superheated vapor state along the entire pipeline. At the same time, the maximum heating temperature is strictly controlled below the critical temperature of thermal decomposition, which completely solves the dual contradiction of sublimation blockage and thermal decomposition pollution.

[0033] (2) The flexible pipe section with double thin-walled overlapping is combined with corrosion-resistant nickel-based alloy material, which greatly reduces bending stiffness while ensuring airtightness, avoids stress corrosion cracking in high temperature and chlorine-containing environment, and significantly improves thermal cycle fatigue life. The dynamic sealing structure of the telescopic joint combined with the low friction coefficient sealing ring and the high temperature resistant elastomer pre-tightening ring realizes long service life and low leakage rate reciprocating sliding seal.

[0034] (3) By establishing a three-level gas pressure cascade gradient of Pm>Po>Pi and a positive pressure protective gas envelope in the intermediate chamber, the highly active precursor will not leak into the external environment even under extreme working conditions where the pipeline is physically damaged.

[0035] (4) The temperature-pressure prediction compensation model is used to filter false alarms of temperature drift and implement a three-level interlock protection system from micro-leakage tolerance compensation to emergency cut-off for severe damage, which takes into account both the continuity of wafer process and the inherent safety under extreme conditions. Attached Figure Description

[0036] To more clearly illustrate the technical solutions of the embodiments of the invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1 This is a schematic diagram of the composite pipeline structure of a solid precursor heat tracing and delivery pipeline system according to the present invention; Figure 2 This is a schematic diagram of the structure at the bend of a solid precursor heat tracing and delivery pipeline system according to the present invention. Figure 3 This is a schematic diagram of the structure of a displacement compensation component of a solid precursor heat tracing and delivery pipeline system according to the present invention. Among them: 99-controller, 10-composite pipeline, 20-gas pipeline, 30-heating element, 40-non-uniform heating component, 50-joint heating component, 60-heat insulation component, 70-displacement compensation component; 101-Inner flow channel, 102-Intermediate chamber, 103-Outer sleeve, 110-First heat tracing section, 120-Second heat tracing section, 130-Third heat tracing section, 140-Fourth heat tracing section; 201-Air replenishment regulating valve; 202-Air pressure sensing device; 401 - Outer arc surface, 402 - Inner arc surface; 61-Pipe support components; 701-Flexible pipe section, 702-Deformable heating jacket, 703-Extendable joint, 704-Sliding sealing structure, 7041-Sealing ring, 7042-Elastomer. Detailed Implementation

[0038] The technical solutions of the embodiments of the invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the invention, and not all embodiments. Based on the embodiments of the invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the invention.

[0039] In the description of this invention, it should be understood that the terms "opening", "upper", "lower", "top", "middle", "inner", etc., which indicate orientation or positional relationship, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the components or elements referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the invention.

[0040] This invention proposes a method for heat-traced transport of solid precursors, comprising: Along the airflow direction, at least two heating sections of the composite pipeline are set with heating temperatures that increase sequentially along the airflow direction to compensate for the heat loss of the gaseous solid precursor during the flow process in the pipeline, so that the gaseous solid precursor is maintained in a superheated vapor state throughout the entire transportation process. A protective gas is introduced into the intermediate chamber of the composite pipeline and a positive pressure is maintained. The pressure change in the intermediate chamber is monitored by a pressure sensor. The leakage status of the composite pipeline is determined based on the pressure change characteristics, and graded safety interlocking actions are executed. The flexible pipe sections and expandable joints connected in series in the composite pipeline absorb the thermal expansion and contraction displacement of the metal components of the composite pipeline caused by temperature changes.

[0041] Specifically, determining the leakage status of the composite pipeline based on pressure change characteristics and executing graded safety interlock actions includes: Obtain the measured air pressure value within the intermediate chamber; The theoretical reference pressure value is calculated based on the current weighted average temperature of each heat tracing section of the composite pipeline. When the absolute value of the deviation between the measured air pressure value and the theoretical reference air pressure value does not exceed the first threshold, the current operating state is maintained. When the absolute value of the deviation exceeds the first threshold and the rate of change of air pressure is within the first rate range, a minor leak is determined to have occurred, and air replenishment is initiated to maintain the air pressure in the intermediate chamber at a level not lower than the safety lower limit. Maintenance is then carried out after the current process is completed. When the rate of change of gas pressure exceeds the second rate threshold, a serious damage or leak is determined, and emergency interlocking actions are performed, including cutting off the supply of solid precursor, shutting off the heating power supply, and increasing the flow rate of protective gas, wherein the second rate threshold is greater than the upper limit of the first rate range.

[0042] The solid precursor heat tracing delivery pipeline system of the present invention is described below with specific embodiments.

[0043] Example 1 like Figures 1 to 3As shown, this embodiment provides a solid-state precursor heated delivery pipeline system applied in advanced 3D NAND and DRAM manufacturing processes. It uses molybdenum dioxide (MoO2Cl2) as a solid-state precursor for atomic layer deposition (ALD) of molybdenum (Mo) thin films. The sublimation temperature of MoO2Cl2 in the source bottle is calibrated to 150°C, and the critical thermal decomposition temperature is approximately 190°C. The delivery pipeline is 22m long, with 8 right-angle bends and 12 VCR metal-faced sealing joints along its path.

[0044] (a) Composite Piping 10 like Figure 1 As shown, the composite pipeline 10 has a three-layer tubular structure coaxially arranged radially from the inside to the outside: an inner flow channel 101, an intermediate chamber 102, and an outer sleeve 103. The inner flow channel 101 is made of seamless Hastelloy C-276 material with an outer diameter of 1 / 2 inch (approximately 12.7 mm) and a wall thickness of 1.24 mm. The inner surface of the inner flow channel 101 is electrochemically polished to a surface roughness Ra ≤ 0.1 μm, achieving an ultra-high purity level to reduce the physical adsorption and retention of gaseous MoO2Cl2 molecules on the pipe wall. This material exhibits significantly superior pitting corrosion resistance and stress corrosion cracking resistance compared to conventional 316L stainless steel in environments with temperatures ≥150℃ and containing free chloride ions.

[0045] The intermediate chamber 102 of this invention is formed by an annular space between a stainless steel tube sleeved outside the inner flow channel 101 and the outer wall of the inner flow channel 101. The stainless steel tube has an outer diameter of 1 inch (approximately 25.4 mm) and a wall thickness of 1.65 mm. An outer sleeve 103 is coaxially sleeved outside the aforementioned stainless steel tube, with an outer diameter of 1.5 inches and made of stainless steel. This forms a three-layer coaxial nested structure of "inner flow channel 101—intermediate chamber 102—outer sleeve 103". The intermediate chamber 102 provides 360° surround heat bath insulation for the inner flow channel 101, significantly reducing radial heat loss from the inner flow channel 101 to the external environment.

[0046] The intermediate chamber 102 of this invention is connected to a protective gas source via a gas pipeline 20. The protective gas source is a high-purity dry nitrogen source with a nitrogen purity of not less than 99.9999% and a dew point below -85°C. A gas supply regulating valve 201 is installed on the gas pipeline 20 of the intermediate chamber 102 to regulate the nitrogen flow rate; a pressure sensor 202 is also installed to monitor the gas pressure inside the intermediate chamber 102 in real time. The pressure sensor 202 is a high-frequency differential pressure sensor with a sampling frequency of not less than 100Hz. Both the gas supply regulating valve 201 and the pressure sensor 202 are electrically connected to the controller 99, forming a closed-loop pressure control system.

[0047] In this embodiment, the inner flow channel 101 is in a high vacuum or low pressure conveying state, and the internal process gas pressure P process Approximately 15 kPa. External Fab ambient atmospheric pressure P ambient The pressure is 101.3 kPa. The controller 99 adjusts the nitrogen pressure P in the intermediate chamber 102 via the supplementary gas regulating valve 201. nitrogen It is precisely maintained at 120 kPa ± 2 kPa.

[0048] Thus, a three-level pressure cascade relationship is established: P nitrogen (120kPa)>P ambient (101.3 kPa) > P process (15kPa). The safety principle of this pneumatic cascade design is as follows: If a microcrack appears in the inner flow channel 101, the high-pressure dry nitrogen gas at 120kPa in the intermediate chamber 102 will preferentially leak into the low-pressure space of the inner flow channel 101 along the pressure gradient direction, forming a nitrogen protective curtain at the crack, preventing external water and oxygen from causing precursor hydrolysis and crystallization at the leak point. At the same time, the pressure monitoring of the intermediate chamber will detect an abnormal signal of pressure leakage towards the vacuum direction. If the outer sleeve 103 is damaged, the nitrogen gas in the intermediate chamber 102 will overflow outward along the pressure gradient, blocking the entry of external humid air into the intermediate chamber. Regardless of the rupture mode, gaseous MoO2Cl2 cannot leak into the external environment through the intermediate chamber 102 due to the reverse pressure difference, achieving intrinsic safety protection of "pressure-encased".

[0049] (ii) Multi-zone heating system like Figure 1 As shown, the multi-temperature zone heating system divides the composite pipeline 10 into four heat tracing sections with independently controllable heating power along the airflow direction: the first heat tracing section 110, the second heat tracing section 120, the third heat tracing section 130, and the fourth heat tracing section 140.

[0050] Heating of each heat tracing section is achieved by heating elements 30 wound around the outer wall of the inner flow channel 101. In this embodiment, the heating element 30 is a mineral-insulated heating cable with a core of nickel-chromium alloy resistance wire, a middle layer of high-purity magnesium oxide mineral insulation, and an outer layer of alloy sheath. It has a heat resistance temperature of not less than 250°C and features high thermal conductivity and uniform radiant heating characteristics.

[0051] The length range and set temperature of each of the four heat tracing sections along the airflow direction are as follows: First heating zone 110 (0~6m section): set temperature 150℃±0.5℃; Second heating section 120 (6~12m section): set temperature 155℃±0.5℃; Third heat tracing section 130 (12~18m section): set temperature 160℃±0.5℃; Fourth heat tracing section 140 (18~22m section): set temperature 165℃±0.5℃.

[0052] The temperature in each section increases gradually in a stepwise positive gradient at 5°C intervals along the airflow direction. The technical principle of this design is as follows: During the flow of gaseous MoO2Cl2 in a 22m long pipeline, the gas's own temperature gradually decreases along the path due to frictional shear with the pipe wall and the adiabatic expansion effect. If constant temperature heating is used, although the pipe wall temperature remains constant, the gas core temperature (i.e., superheat) will gradually decrease to near the sublimation temperature in the downstream region. This invention increases the pipe wall heating temperature segment by segment along the airflow direction, actively supplementing the airflow with incremental heating in each segment, so that the MoO2Cl2 gas maintains a superheat much higher than its sublimation temperature (150°C) throughout the entire process—in this embodiment, the superheat is not lower than 15°C, which, from a thermodynamic point of view, disrupts the kinetic conditions for sublimation and crystallization. At the same time, the highest set temperature (165°C) of the fourth heating section 140 is much lower than the critical temperature for thermal decomposition of MoO2Cl2 (approximately 190°C), ensuring that the precursor will not undergo thermal decomposition due to overheating during the ultra-long process.

[0053] The outer surface of the heating element 30 is covered with a multi-layer stainless steel foil heat insulation shield with a thickness of 6 mm. This shield is composed of multiple layers of stainless steel foil and spaced vacuum layers, which can effectively suppress radiative heat loss and shield external radio frequency interference.

[0054] (III) Locally Enhanced Heat Transfer Components In a 22m long pipeline, right-angle elbows, VCR joints, and pipe support clamps constitute three types of concentrated heat dissipation areas, which are potential temperature depressions. This embodiment sets up corresponding localized enhanced heat transfer components for the above three types of concentrated heat dissipation areas.

[0055] (1) Non-uniform heating component at the bend 40 Reference Figure 2 At the 90° bend, the surface area of ​​the outer arc surface (the side with the largest radius of curvature) of the inner flow channel 101 is significantly larger than that of the inner arc surface (the side with the smallest radius of curvature). This results in the outer arc surface losing much more heat to the external environment through radiation and convection than the inner arc surface. If uniform winding heating with equal thickness is used, obvious local low temperatures will appear on the outer arc surface.

[0056] To address the aforementioned issues, a non-uniform heating element 40 is applied to the elbow. This non-uniform heating element 40 is a resistance heating layer with a variable thickness, its thickness gradually decreasing radially from the outer arc surface 401 to the inner arc surface 402 of the elbow: the thickness at the outer arc surface 401 is 5 mm, and the thickness at the inner arc surface 402 is 2 mm. Simultaneously, the spiral winding density of the resistance heating wire inside the non-uniform heating element 40 is higher in the outer arc surface region than in the inner arc surface region, resulting in a heating power of approximately 0.8 W / cm² at the outer arc surface.2 The heating power per unit area at the inner arc surface is approximately 0.3 W / cm². 2 This asymmetric, variable-power precise thermal compensation design effectively neutralizes the uneven heat dissipation caused by the geometric curvature of the elbow, and the temperature difference between the overall inner wall of the elbow and the adjacent straight pipe section is controlled within ±0.5℃.

[0057] (2) Joint heating component 50 at the joint Still refer to Figure 2 The pipeline includes 12 VCR metal-faced seal joints, each connecting two pipe sections. The joint's metal body has a large volume and high heat capacity, with its convective and radiative heat dissipation approximately 2.5 times that of a straight pipe section of the same length. Each VCR joint is externally covered with a joint heating element 50.

[0058] The joint heating element 50 is a symmetrical semi-circular tile structure made of high thermal conductivity brass (thermal conductivity approximately 120 W / (m·K)). The two semi-circular tiles fit tightly together on the outer wall of the joint. Two independent heating elements are symmetrically embedded inside the joint heating element 50, located within the two semi-circular tiles respectively. A Pt100 platinum resistance temperature sensor is attached to the outer surface of the joint heating element 50, forming a closed-loop PID temperature control circuit with the controller 99 (or an independent temperature control module).

[0059] In actual operation, the controller 99 sets the operating temperature of the joint heating element 50 to be 3℃~5℃ higher than the set temperature of its respective heat tracing section. For example, for the joint located in the third heat tracing section 130 (set to 160℃), the constant temperature of its joint heating element 50 is controlled at 163℃~165℃. By applying a slight local overheating to the joint, the additional heat loss caused by the large heat capacity at the joint is effectively compensated, and the temperature depression along the joint is eliminated.

[0060] (3) Thermal insulation component 60 at the support Reference Figure 2 The composite pipeline 10 is suspended along the factory ceiling grid frame by multiple pipeline supports 61. Without thermal insulation, the pipeline supports 61 will act as heat bridges, continuously dissipating heat from inside the pipeline to the cooler steel frame structure of the factory through the solid metal conduction path, resulting in obvious cold spots at the clamping points of the supports.

[0061] A heat insulation component 60 is fitted at the contact interface between the pipe support 61 and the outer sleeve 103. In this embodiment, the heat insulation component 60 is an annular gasket made of high-temperature sintered zirconia ceramic. The thermal conductivity of zirconia ceramic is less than 2 W / (m·K), which is only about one-eighth to one-tenth of the thermal conductivity of stainless steel. The intervention of the heat insulation component 60 effectively blocks solid heat conduction along the pipe support path, fundamentally eliminating cold spots at the support point.

[0062] (iv) Displacement compensation component 70 When a 22m long Hastelloy C-276 pipe is preheated from room temperature (approximately 20°C) to its maximum operating temperature of 165°C, the inner flow channel 101 will experience significant axial linear thermal expansion. The average coefficient of linear expansion of Hastelloy C-276 in the 20°C to 200°C range is approximately 11.2 × 10⁻⁶. -6 The axial thermal expansion displacement ΔL is calculated as follows: / ℃ ΔL = α × L × ΔT = 11.2 × 10 -6 ×22000×(165-20)≈35.7mm.

[0063] If the axial ends of the pipeline are rigidly constrained, the displacement will generate huge thermal stress at the pipeline bends, which may lead to plastic deformation of the pipe wall, weld cracking, or loosening of the joint seal. The displacement compensation component 70 is used to flexibly absorb the above-mentioned axial and radial thermal displacements.

[0064] Reference Figure 3 The displacement compensation component 70 is connected in series at approximately the center (about 11m) of a 22m long straight pipe section, and includes a flexible pipe section 701, a deformable heating jacket 702, and a telescopic joint 703.

[0065] The flexible pipe section 701 is installed on the inner flow channel 101 and is a double-layer coaxial metal bellows. The base material is the same as that of the inner flow channel 101, which is Hastelloy C-276. The double-layer coaxial structure is made of two ultra-thin bellows with a wall thickness of 0.20mm ± 0.02mm, coaxially nested together—a small gap is left between the outer trough of the inner bellows and the inner crest of the outer bellows. The two ends of the two bellows are welded and sealed to adjacent straight pipe sections. The use of Hastelloy C-276 material ensures that the bellows will not experience stress corrosion cracking in high-temperature and trace free chloride ion corrosive environments.

[0066] The double-layer coaxial design offers two key advantages: First, it provides physical redundancy—even if the inner corrugated pipe develops microcracks due to fatigue, the outer corrugated pipe can still maintain process airtightness; second, compared with the single-layer thick-walled corrugated pipe, the double-layer ultra-thin-walled overlapping significantly reduces bending stiffness (bending stiffness is proportional to the cube of the wall thickness) under the same pressure-bearing capacity, significantly reducing the force required for flexural deformation, and increasing fatigue life by more than 3 times during thousands of thermal cycles.

[0067] A deformable heating jacket 702 is coaxially fitted around the flexible pipe section 701. This heating jacket is woven from fine nickel-chromium alloy heating wires embedded in a flexible braided mesh. It can synchronously stretch and deform by up to ±25% without breaking as the flexible pipe section 701 expands and contracts, maintaining a uniform constant power output throughout the entire stretching stroke. The deformable heating jacket 702 ensures that the flexible pipe section 701 maintains the same operating temperature (150℃~165℃) as the adjacent straight pipe section at any expansion or contraction position, preventing the flexible pipe section 701 from becoming a new cold spot.

[0068] The outer sleeve 103 is disconnected at a position corresponding to the flexible tube section 701 and is fitted with a telescopic joint 703. The telescopic joint 703 is used to accommodate the expansion displacement of the inner flow channel 101 transmitted to the corresponding axial movement of the outer sleeve 103, while maintaining the airtightness of the intermediate chamber 102.

[0069] The sliding surface of the inner wall of the telescopic joint 703 is provided with a sliding sealing structure 704. The sliding sealing structure 704 is a multi-layer structure, including a sealing ring 7041 that is in close contact with the inner side of the sliding friction surface and an elastic body 7042 that is disposed on the outer side of the sealing ring 7041.

[0070] The sealing ring 7041 is a component that directly withstands high temperatures and minimal reciprocating sliding friction, and is made of polytetrafluoroethylene (PTFE) composite material. Its specific formulation is: 15 wt% carbon fiber and 5 wt% graphite filled into a PTFE matrix. The carbon fiber provides a high-strength skeleton and excellent creep resistance, while the graphite provides self-lubrication, resulting in a coefficient of friction of less than 0.05 for the sealing ring 7041, minimizing scratches on the mating metal surfaces during reciprocating sliding.

[0071] Elastomer 7042 provides a continuous and stable radial preload to sealing ring 7041, ensuring that the sealing lip of sealing ring 7041 always remains tightly against the sliding mating surface. Elastomer 7042 is made of perfluoroether rubber with a Shore A hardness of 80. FFKM operates at 200°C for extended periods without hardening, thermal aging, or permanent compression deformation, consistently providing a stable sealing preload. In a cumulative 3000 thermal cycle tensile life test, the helium leakage rate of this sliding seal structure 704 consistently remained less than 1×10⁻⁶. -10 Pa·m 3 Excellent level of / s.

[0072] (v) Leakage Protection System The leakage protection system consists of a protective gas source, a gas replenishment regulating valve 201, a gas pressure sensing device 202, a controller 99, a process shut-off valve 21, and multiple temperature sensors distributed along the process (in this embodiment, there are 12 Pt100 platinum resistance temperature sensors, which are arranged on the outer wall of the inner layer flow channel 101 of each heat tracing section).

[0073] Since the intermediate chamber 102 is a sealed space, the nitrogen gas inside it will undergo significant natural expansion and upward drift as the system heats up from room temperature to the operating temperature (150℃~165℃), according to the ideal gas law. Under the full-load operating conditions of this embodiment, the weighted average temperature T of 12 temperature measuring points... w ≈157.5℃ (i.e., absolute temperature 430.65K). Controller 99 calculates the theoretical reference pressure P based on the following temperature-pressure prediction compensation model. ref : P ref =P0×T w / T0 In the formula, P0 = 120 kPa is the initial calibration pressure (calibrated at an initial temperature T0 = 20 °C = 293.15 K). Substituting the data from this embodiment: P ref =120×430.65 / 293.15≈176.3kPa That is, due to the expansion caused by temperature rise, the air pressure in the intermediate chamber 102 naturally rose by about 56.3 kPa. This change is a normal physical phenomenon.

[0074] The controller 99 synchronously acquires the measured air pressure value P returned by the air pressure sensor 202. act Calculate the deviation ΔP=P act -P ref Based on a sliding time window (60s wide), the pressure change rate dP / dt is calculated, and graded interlocking protection is executed according to the following three-level logic: Level 1: When |ΔP|≤3kPa, the controller 99 determines that the system is in normal operation. The slight fluctuation of the measured air pressure is completely within the expected range of the temperature-pressure prediction compensation model and is a normal physical phenomenon of temperature rise and expansion, which does not trigger any alarm or protection action.

[0075] Level 2: When |ΔP|>3 kPa (i.e., the measured air pressure is significantly lower than the theoretical reference value after temperature compensation), and the rate of change of air pressure dP / dt within a one-minute sliding window satisfies -0.5 kPa / min ≤ dP / dt ≤ -0.1 kPa / min (monotonically decreasing slowly), the controller determines that a minor leak with a controllable rate has occurred at some point in the pipeline. At this time, a Level 1 audible and visual alarm is triggered to notify maintenance personnel.

[0076] In the second stage, due to the pressure cascading relationship, the leakage direction is guaranteed to be unidirectional overflow of nitrogen from the intermediate chamber 102 to the inner tube or to the external environment, and the MoO2Cl2 precursor will not leak. Moreover, the current wafer process is in operation (the value of the wafers in production is relatively high). The control strategy of the controller 99 is: not to immediately cut off the process, but to control the gas supply regulating valve 201 to supply a small amount of constant pressure nitrogen, so as to dynamically maintain the gas pressure in the intermediate chamber 102 at a safe lower limit of above 115kPa. The leak point is suppressed by the continuous positive pressure nitrogen air curtain. After ensuring that the current batch of wafers safely completes the entire process, the operation and maintenance personnel are notified to carry out troubleshooting and maintenance within the planned shutdown window.

[0077] Level 3: When the rate of change of air pressure dP / dt is less than -5kPa / s (i.e., the air pressure drops suddenly within a second, indicating severe damage such as rupture or breakage of the inner or outer pipe), the controller 99 will execute the following interlock protection sequence within a time of no more than 50ms (the actual measured response time is about 30ms): ① Instantly shut off the normally closed pneumatic process shut-off valve 21 located on the SDS outlet side and the process gas inlet valve on the process main unit inlet side, stopping the supply of precursor to the pipeline. ②Shut down the heating power supply of all four heat tracing sections to prevent local overheating of the pipeline due to continuous heating without airflow cooling. ③ Fully open the nitrogen supply proportional valve to inject high-purity dry nitrogen into the intermediate chamber 102 and the inner flow channel 101 at the maximum design flow rate. Use positive pressure inert nitrogen to purge and dilute in the reverse direction along the pipeline at a high flow rate, pushing back the residual highly active MoO2Cl2 gas and sealing it on the source bottle side to ensure that no hazardous materials escape into the clean room environment.

[0078] (vi) Work process Upon system startup, the protective gas source is first activated to fill the intermediate chamber 102 with high-purity dry nitrogen, which is controlled in a closed loop by the gas supply regulating valve 201 and the pressure sensor 202 to 120 kPa ± 2 kPa. Then, the heating elements 30 of the four heat tracing sections are activated, each section independently heating to its set temperature (150℃ / 155℃ / 160℃ / 165℃) in PID mode. During the heating process, the flexible tube section 701 of the displacement compensation component 70 gradually stretches as the temperature rises, absorbing axial thermal expansion displacement, and the telescopic joint 703 slides accordingly, while the sliding sealing structure 704 maintains an airtight seal on the intermediate chamber 102. After the temperature of each section stabilizes, the SDS end is opened, and gaseous MoO2Cl2 enters the inner flow channel 101, and is transported to the process chamber of the main process unit in a superheated vapor state under the maintenance of the positive gradient heat tracing temperature along the flow path. During operation, the leakage protection system monitors the pressure of the intermediate chamber 102 in real time and implements graded interlocking protection.

[0079] Example 2 The main difference between this embodiment and Embodiment 1 is that the solid precursor is molybdenum pentachloride (MoCl5), the transport distance is 31.5m, and it is used in the deposition of molybdenum thin films for control electrodes in advanced logic chip manufacturing processes.

[0080] MoCl5 is a dark green crystal at room temperature, with a melting point of approximately 194°C under normal pressure. Its effective sublimation temperature under high vacuum conditions is approximately 170°C, and its critical thermal decomposition temperature is approximately 200°C, with a temperature control window of only 30°C. It exhibits extremely high chemical reactivity, instantly hydrolyzing upon contact with water to release highly corrosive HCl gas and chloride ions.

[0081] (a) Composite Piping 10 The inner flow channel 101, the flexible pipe section 701, and all metal components in direct contact with the process medium are made of Hastelloy C-276. Because MoCl5 is more corrosive than MoO2Cl2 in the high-temperature sublimation vapor phase, conventional 316L stainless steel will show severe intergranular corrosion within a few weeks, making Hastelloy C-276 a necessary choice.

[0082] Nitrogen pressure P in intermediate chamber 102 nitrogen =120kPa±2kPa, process gas pressure P in inner layer flow channel 101 process Approximately 12 kPa, P ambient =101.3kPa, forming the same three-level cascade relationship as in Example 1.

[0083] (ii) Multi-zone heating system The set temperature and length ranges for the four heat tracing sections are as follows: First heating section 110 (0~8m): 170℃±0.5℃; Second heating section 120 (8~16m): 175℃±0.5℃; Third heating section 130 (16~24m): 180℃±0.5℃; Fourth heating section 140 (24~31.5m): 185℃±0.5℃.

[0084] The temperature difference between adjacent sections is maintained at 5℃, and the superheat is always maintained at no less than 15℃. The maximum temperature of the fourth heating section 140℃ is strictly locked below the critical temperature of MoCl5 thermal decomposition of 200℃, with a safety margin of 15℃.

[0085] (III) Locally Enhanced Heat Transfer Components The heating power of the outer arc surface of the non-uniform heating component 40 at the bend is adjusted to 0.9W / cm. 2 The inner arc surface was adjusted to 0.35 W / cm. 2The temperature difference between the inner wall of the elbow and the adjacent straight pipe section is controlled within ±0.3℃. The constant temperature setting of the joint heating component 50 is 4℃~5℃ higher than that of the section it is in. The thermal conductivity of the zirconia ceramic of the insulation component 60 is not greater than 1.8W / (m·K).

[0086] (iv) Displacement compensation component 70 The axial thermal expansion displacement ΔL of a 31.5m Hastelloy C-276 pipe heated from room temperature (20℃) to 185℃ is 11.2 × 10⁻⁶. -6 ×31500×(185-20)≈58.2mm. The stroke of the flexible pipe section 701 and the telescopic joint 703 is correspondingly lengthened. In the sliding sealing structure 704 of the telescopic joint 703, considering the continuous high temperature of 185℃, the FFKM elastomer 7042 is selected with a temperature resistance rating of not less than 230℃, and the other materials are selected in the same way as in Example 1. After continuous high temperature at 185℃ and a cumulative 3000 thermal cycle fatigue tests, the helium leakage rate in the middle cavity still remains less than 1×10. -10 Pa·m 3 / s level.

[0087] (v) Leakage Protection System When running at full load, the weighted average temperature T at 12 temperature measurement points along the path w ≈177.5℃ (i.e., 450.65K). Theoretical reference pressure: P ref =120×450.65 / 293.15≈184.5kPa The threshold values ​​for the three-level interlocking are the same as in Example 1: the first threshold is 3 kPa, the first rate range is -0.5 to -0.1 kPa / min, and the second rate threshold is -5 kPa / s. The measured response time for the third level is approximately 40 ms.

[0088] (vi) Work process It is basically the same as Example 1, except that the set value of the heating temperature of each section is higher and the time to heat up to full load is slightly longer.

[0089] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0090] The preferred embodiments of the invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A solid precursor heat tracing and delivery pipeline system, characterized in that, include: A composite pipeline has an inner flow channel, an intermediate chamber and an outer sleeve arranged radially from the inside to the outside. The inner flow channel is connected between the gas source end and the gas consumption end of the solid precursor and is used to transport the gas phase solid precursor. A multi-temperature zone heating system is provided with at least two heat tracing sections whose heating power can be independently controlled along the airflow direction of the composite pipeline, and the heating temperature of each heat tracing section is controlled to increase sequentially along the airflow direction to compensate for the heat loss of the gaseous solid precursor during the flow process in the pipeline. A locally enhanced heat transfer component is disposed on a local part of the composite pipe where the heat dissipation rate is higher than that of the straight pipe section. It is used to apply a larger heating power per unit area and / or a smaller thermal conductivity coefficient to the local part compared to the adjacent straight pipe section, so as to suppress the temperature of the local part from being lower than that of the adjacent straight pipe section. A displacement compensation component, which is connected in series in the straight section of the composite pipeline, includes at least one flexible pipe section disposed in the inner flow channel and a telescopic joint disposed in the outer sleeve, for absorbing the thermal expansion and contraction displacement of the metal components of the composite pipeline caused by temperature changes. The leakage protection system fills the intermediate chamber with protective gas and maintains it at a positive pressure higher than the external ambient pressure. It monitors the pressure changes in the intermediate chamber through a pressure sensor and determines the leakage status of the composite pipeline based on the characteristics of the pressure changes, and executes corresponding safety interlock actions. The inner flow channel is composed of a first metal tube, the intermediate chamber is composed of an annular space between a second metal tube sleeved outside the first metal tube and the outer wall of the first metal tube, and the outer sleeve is coaxially sleeved outside the second metal tube. The pressure values ​​Pm of the protective gas in the intermediate chamber, Pi of the process gas in the inner flow channel, and Po of the external atmospheric pressure satisfy: Pm>Po>Pi, so that the gas phase solid precursor is always maintained in a superheated vapor state throughout the entire process, while the maximum heating temperature is controlled below the thermal decomposition critical temperature.

2. The system according to claim 1, characterized in that: The multi-temperature zone heating system supplies heat to each of the heat-tracing sections separately through heating elements wound around or attached to the outer wall of the inner flow channel.

3. The system according to claim 1, characterized in that: The heat tracing sections are two, three, or four; the heating temperature difference between adjacent heat tracing sections is 3℃~10℃; the heating temperature of the heat tracing section closest to the gas-using end is lower than the thermal decomposition critical temperature of the solid precursor.

4. The system according to claim 1, characterized in that: The locally enhanced heat transfer component includes at least one of the following three: The non-uniform heating component installed in the bend section of the composite pipeline provides a greater heating power per unit area in the outer region of the bend than in the inner region. The heating component installed at the pipe section connection joint of the composite pipeline has at least one independent heating element embedded inside, which is used to provide the connection joint with additional heat that is higher than the heating temperature of the heat tracing section thereon than a preset value. The thermal insulation component installed between the pipe support and the outer sleeve of the composite pipeline has a material with a lower thermal conductivity than the material of the outer sleeve.

5. The system according to claim 4, characterized in that: The thickness of the non-uniform heating component decreases from the outer side of the bend to the inner side of the bend.

6. The system according to claim 4, characterized in that: The heating component is a dual-structure made of metal material, with two symmetrically distributed independent heating elements embedded inside, and equipped with a temperature sensor for closed-loop temperature control.

7. The system according to claim 1, characterized in that: The leakage protection system performs graded interlocking protection actions based on the deviation between the measured air pressure value in the intermediate chamber and the theoretical reference air pressure value calculated based on the current temperature distribution, as well as the time change rate of the air pressure.

8. The system according to claim 7, characterized in that: The hierarchical interlocking protection actions include: When the absolute value of the deviation does not exceed the first threshold, the current operating parameters remain unchanged; When the absolute value of the deviation exceeds the first threshold and the absolute value of the time change rate is within the first rate range, a minor leak is determined to have occurred, an alarm is triggered, and protective gas supply is initiated to maintain the gas pressure in the intermediate chamber at a level not lower than the safety lower limit. When the absolute value of the time change rate exceeds the second rate threshold, a serious damage or leak is determined, and emergency interlock actions are performed to cut off the precursor supply, shut down the heating power supply, and / or increase the protective gas charging flow rate, wherein the second rate threshold is greater than the upper limit of the first rate range.

9. A method for heat-traced transport of a solid precursor, characterized in that, The system applied to any one of claims 1 to 8 comprises: Along the airflow direction, at least two heating sections of the composite pipeline are set with heating temperatures that increase sequentially along the airflow direction to compensate for the heat loss of the gaseous solid precursor during the flow process in the pipeline, so that the gaseous solid precursor is maintained in a superheated vapor state throughout the entire transportation process. A protective gas is introduced into the intermediate chamber of the composite pipeline and a positive pressure is maintained. The pressure change in the intermediate chamber is monitored by a pressure sensor. The leakage status of the composite pipeline is determined based on the pressure change characteristics, and graded safety interlocking actions are executed. The flexible pipe sections and expandable joints connected in series in the composite pipeline absorb the thermal expansion and contraction displacement of the metal components of the composite pipeline caused by temperature changes.

10. The method according to claim 9, characterized in that: The step of determining the leakage status of the composite pipeline based on the characteristics of air pressure changes and executing graded safety interlock actions includes: Obtain the measured air pressure value within the intermediate chamber; The theoretical reference pressure value is calculated based on the current weighted average temperature of each heat tracing section of the composite pipeline. When the absolute value of the deviation between the measured air pressure value and the theoretical reference air pressure value does not exceed the first threshold, the current operating state is maintained. When the absolute value of the deviation exceeds the first threshold and the rate of change of air pressure is within the first rate range, a minor leak is determined to have occurred, and air replenishment is initiated to maintain the air pressure in the intermediate chamber at a level not lower than the safety lower limit. Maintenance is then carried out after the current process is completed. When the rate of change of gas pressure exceeds the second rate threshold, a serious damage or leak is determined, and emergency interlocking actions are performed, including cutting off the supply of solid precursor, shutting off the heating power supply, and increasing the flow rate of protective gas, wherein the second rate threshold is greater than the upper limit of the first rate range.

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