A passivation system for a seamless steel cylinder for electronic special gas based on silicon and a method thereof

Abstract

The application discloses a silicon-based electronic special gas steel seamless cylinder passivation system and method, which comprises a passivation pipeline, a cylinder, a temperature control device, and a cylinder valve. The passivation pipeline is provided with a cylinder interface, a qualified product interface, a vacuum interface, a protective gas interface and a waste liquid discharge port. The cylinder valve is vertically arranged in an inverted position, and is communicated with the cylinder interface. The temperature control device is arranged outside the cylinder and is used for realizing the reciprocating circulation of the gasification of liquid chlorosilane material in the cylinder and the condensation of the gaseous material in the cylinder. The passivation and self-flushing of the inner wall of the cylinder are high in efficiency and good in effect. After the passivated cylinder is filled with silicon-based electronic special gas products, the impurity content is low, and the quality is stable for a long time.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of electronic special gas disassembling, and particularly relates to a steel seamless cylinder passivation system for silicon-based electronic special gas and a method thereof. BACKGROUND

[0002] The silicon-based electronic special gas mainly includes electronic-grade dichlorodihydrogen silicon, electronic-grade trichlorohydrogen silicon and electronic-grade silicon tetrachloride, and is mainly used for silicon source of silicon epitaxial growth and large-scale integrated circuit silicon epitaxy, is a source material for low-temperature silicon deposition with excellent performance, and is widely applied.

[0003] The silicon-based electronic special gas has extremely high requirements for impurities, and the content of each metal and non-metal impurity is required to be less than or equal to 1 ppb, or even lower. The quality of the steel cylinder has a direct impact on the quality of the stored high-purity material, and the cleanliness of the inner wall of the steel seamless cylinder is directly related to the quality of the delivered product. Before use, the steel seamless cylinder needs to be passivated and cleaned in advance with the product stored therein, and after detection, the cylinder can be put into normal use.

[0004] The silicon-based electronic special gas has certain particularity compared with other gases. The silicon-based electronic special gas is in liquid phase at normal temperature and pressure, and has strong corrosiveness. Various impurities remaining on the inner wall of the cylinder during processing will continuously precipitate, seriously affecting the quality of the product after disassembling. Before the cylinder is formally put into use, the trace metal impurities remaining on the inner wall of the cylinder need to be thoroughly cleaned and replaced, and the inner wall of the cylinder is passivated to form a stable passivation film, so as to avoid continuous precipitation of metal impurities and improve the quality stability of the product stored in the cylinder.

[0005] In the related art, qualified silicon-based electronic gas products are filled into the cylinder according to a filling coefficient of 90% to 95%, and the product is pressed out after being left to stand or horizontally rolling for a long time to complete cleaning and passivation. Then the product is filled again for cleaning and passivation, and the process is repeated until the product after passivation meets the quality requirements of the final product. Based on this, in the prior art, the steel seamless cylinder passivation technology for electronic special gas has the following disadvantages: the water in the cylinder is removed well, but the trace metal impurities on the inner wall of the cylinder cannot be effectively cleaned, the passivation of the cylinder for the silicon-based electronic special gas with strong corrosiveness is time-consuming, high in cost and complex in process, a large amount of qualified products are consumed, a large amount of waste liquid is generated, and the rolling passivation and cleaning method is time-consuming and labor-intensive. SUMMARY

[0006] In order to solve the above problems in the prior art, the application aims to provide a steel seamless cylinder passivation system for silicon-based electronic special gas and a method thereof. The passivation and self-flushing of the inner wall of the cylinder are high in efficiency and good in effect. The impurity content of the cylinder after passivation is low, and the quality is stable for a long time after the cylinder is filled with silicon-based electronic special gas products.

[0007] One of the purposes of the present application is to provide a silicon-based electronic special gas steel seamless cylinder passivation system, comprising

[0008] A passivation pipeline is provided with a cylinder interface, a qualified product interface, a vacuum interface, a protective gas interface and a waste liquid discharge port;

[0009] A cylinder is set vertically upside down, and the cylinder valve is in communication with the cylinder interface for introducing qualified products, pressing out cleaning waste liquid and replacing protective gas into the cylinder;

[0010] A temperature control device is arranged outside the cylinder for realizing the reciprocating of the gasification of liquid chlorosilane material in the cylinder and the condensation cycle of the gaseous material in the cylinder;

[0011] A qualified product storage tank is connected with the qualified product interface for filling liquid chlorosilane for cleaning and passivation into the cylinder;

[0012] A vacuum pump is connected with the vacuum interface, and the vacuum pump is used for vacuumizing the passivation pipeline and the cylinder;

[0013] A protective gas source is connected with the protective gas interface for supplying and replacing protective gas to the passivation pipeline and the cylinder;

[0014] A waste liquid tank is connected with the waste liquid discharge port for storing the cleaned waste liquid discharged from the cylinder.

[0015] As a preferred scheme, the temperature control device comprises

[0016] A first temperature control unit is arranged at the bottle body position of the cylinder close to the valve for heating the lower section of the inverted cylinder close to the valve; for heating the liquid phase material in the inverted cylinder to a gaseous state, and filling the internal space of the cylinder, the gaseous material forms a passivation film after contacting the inner surface of the cylinder;

[0017] A second temperature control unit is arranged at the bottle body position of the cylinder away from the valve for condensing the gaseous phase material in the internal part of the upper section of the inverted cylinder away from the valve, and cleaning the inner wall of the bottle body by the condensed material to remove the trace impurities remaining in the inner wall of the cylinder.

[0018] The temperature control temperature of the first temperature control unit is greater than that of the second temperature control unit, so as to realize the reciprocating of the vaporization and condensation of the material in the cylinder.

[0019] As a preferred scheme, a temperature controller is further provided, which is connected with the first temperature control unit signal and the second temperature control unit signal respectively for controlling the temperature of the upper and lower sections of the cylinder body.

[0020] As a preferred solution, a pressure gauge is arranged on the passivation pipeline to detect the pressure of the passivation pipeline in real time.

[0021] As a preferred solution, the gas cylinder is provided with a plurality of gas cylinder interfaces connected in parallel to the passivation pipeline.

[0022] The second object of the present application is to provide a method for passivating a steel seamless gas cylinder for silicon-based electronic special gas, characterized in that:

[0023] Step one, the gas cylinder is connected to the passivation system in an inverted manner, and the passivation pipeline is pressure-qualified,

[0024] Step two, the passivation pipeline is pressurized by a protective gas source,

[0025] Step three, the passivation pipeline is vacuumized by a vacuum pump;

[0026] Step four, steps two and three are repeated a predetermined number of times;

[0027] Step five, the gas cylinder is vacuumized by a vacuum pump;

[0028] Step six, a certain amount of material is sent into the gas cylinder from a qualified product tank;

[0029] Step seven, the first temperature control unit and the second temperature control unit are controlled to a preset temperature by a temperature controller according to different materials;

[0030] Step eight, the liquid material in the lower part of the inverted gas cylinder continuously vaporizes, and the gaseous material entering the upper part of the gas cylinder condenses on the inner wall of the gas cylinder, and the vaporization and condensation of the material circulate between the upper and lower parts of the gas cylinder space;

[0031] Step nine, heat for a certain period of time, stop heating after the predetermined passivation and cleaning are completed, and when the temperature of the gas cylinder drops to a certain temperature, use the protective gas source to completely press the material in the gas cylinder to a waste liquid tank;

[0032] Step ten, the gas cylinder and the passivation pipeline are vacuumized by a vacuum pump;

[0033] Step eleven, the gas cylinder and the passivation pipeline are pressurized by a protective gas source;

[0034] Step twelve, steps ten and eleven are repeated a predetermined number of times;

[0035] Step thirteen, maintain a slight positive pressure of 10kPa-50kPa in the passivation pipeline, and disassemble the gas cylinder to complete the passivation.

[0036] As a preferred solution, in step six, the volume of the material sent into the gas cylinder from the qualified product tank accounts for 3%-5% of the volume of the gas cylinder.

[0037] As a preferred solution, in the step seven, the preset temperature of the second temperature control unit is 5-20℃ lower than the preset temperature of the first temperature control unit.

[0038] As a preferred solution, in the step nine, the heating time is 24h-48h.

[0039] Advantages

[0040] Firstly, the device can realize gas phase passivation and liquid phase self-flushing by setting the gas cylinder, qualified product storage tank, vacuum pump, protective gas source and waste liquid tank on the passivation pipeline and controlling the temperature of the gas cylinder by the temperature control device. The close cooperation of the vacuum pump, protective gas source, qualified product storage tank and waste liquid tank in the system can effectively solve the replacement of the gas circuit and gas cylinder in the device, pressure test, qualified product supply and waste liquid discharge, greatly improve the efficiency of the gas cylinder passivation, save the electronic grade product, and solve the problems of slow passivation rate, low passivation efficiency, high cost and high consumption of mother liquor in the existing gas cylinder passivation technology. The device has reasonable structure, simple operation, is conducive to scale-up and improves production efficiency.

[0041] Secondly, the structure of the passivation system is reasonably optimized. When the gas cylinder is installed, it needs to be inverted and set. The first temperature control unit is arranged at the lower segment of the inverted gas cylinder body to heat and gasify the liquid chlorosilane stored in the segment. The preset temperature of the second temperature control unit arranged at the upper segment of the inverted gas cylinder body is lower than that of the first heating unit. Therefore, the second temperature control unit is essentially used to condense the gaseous chlorosilane generated in the space of the segment after heat exchange, and the condensed liquid beads flow down along the side wall of the cylinder body from top to bottom, so as to remove the trace impurities remaining on the inner wall of the gas cylinder. The gasification and condensation of chlorosilane material are circularly carried out between the upper and lower segments of the gas cylinder, which can effectively improve the passivation and cleaning effect.

[0042] Thirdly, the passivation process method is optimized. The passivation system with the above specific connection mode is used for organic cooperation. First, the silicon-based electronic special gas is used to high-temperature passivate the steel seamless gas cylinder for sub-packaging. At a relatively high temperature, the passivation speed is greatly improved. The gas phase passivation and liquid phase self-flushing are realized in the gas cylinder, which has excellent removal effect on the trace impurities remaining on the inner wall of the gas cylinder, and shortens the cleaning and passivation period. Because of the gas phase passivation, compared with complete liquid phase passivation, the consumption of qualified products to be filled is reduced from 90%-95% of the volume of the gas cylinder to 3%-5% per passivation, the use amount of silicon-based electronic special gas product is greatly reduced, and the production cost is obviously reduced. BRIEF DESCRIPTION OF DRAWINGS

[0043] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description only show some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from these drawings without any creative effort.

[0044] Figure 1 It is a structural schematic diagram of the passivation system of the present application.

[0045] Figure 2 It is a schematic diagram of the state change of the material in the gas cylinder during the passivation process.

[0046] The marks in the figure: 1, gas cylinder, 2, cylinder valve, 3, pressure gauge, 4, vacuum pump, 5, protective gas source, 6, qualified product tank, 7, waste liquid tank, 8, first temperature control unit, 9, second temperature control unit, 10, passivation pipeline, 11, temperature controller I, 12, temperature controller II; 100, inverted gas cylinder lower section, 200, inverted gas cylinder upper section, 300, liquid phase volatilization state schematic, 400, gas phase condensation state schematic. DETAILED DESCRIPTION

[0047] The present application will be described in detail below through exemplary embodiments. However, it should be understood that the elements, structures and features in one embodiment can also be beneficially combined into other embodiments without further description.

[0048] It should be noted that: unless otherwise defined, the technical terms or scientific terms used in this article should be understood as the usual meaning understood by those skilled in the art to which the present application belongs. The "one", "a" or "the" and similar words used in the patent application description and claims of the present application do not represent quantity limitation, but indicate the existence of at least one. The "including" or "containing" and similar words indicate that the elements or objects appearing before "including" or "containing" cover the elements or objects listed after "including" or "containing" and their equivalents, but do not exclude other elements or objects with the same function.

[0049] In polysilicon production enterprises, the removal of trace impurities is an important problem that needs to be solved to improve the product grade of high-purity chlorosilane. The existing gas cylinder passivation technology has good effect on the removal of moisture in the gas cylinder, but it cannot effectively clean the trace metal impurities on the inner wall surface of the gas cylinder. In order to achieve the required content of trace impurities in the gas cylinder, it is necessary to use a large amount of qualified products for displacement cleaning, which will generate a lot of waste liquid, resulting in cost increase and product waste. In view of this, the present application proposes the following solutions.

[0050] A typical embodiment of the present application is as follows: as shown in the figure, the embodiment provides a silicon-based electronic special gas steel seamless cylinder passivation system, which comprises a passivation pipeline 10, a cylinder 1, a temperature control device, a qualified product storage tank 6, a vacuum pump 4, a protective gas source 5 and a waste liquid tank 7, wherein the passivation pipeline 10 is provided with a cylinder interface, a qualified product interface, a vacuum interface, a protective gas interface and a waste liquid discharge port, and the above interfaces and the discharge port are connected to realize the communication of each component in the system, so that the cylinder passivation system is connected as a closely coordinated device. After the cylinder in the present application is passivated and cleaned, the trace impurity content of the chlorosilane contained therein can reach the PPb level.

[0051] In order to improve the passivation and cleaning effect, the cylinder 10 is vertically arranged in a downward inverted bottle valve 2 mode, the bottle body of the cylinder 1 is divided into an upper segment and a lower segment, the upper segment accounts for about 4 / 5 of the length of the entire bottle body, and the lower segment accounts for about 1 / 5 of the length of the entire bottle body, the inside of the cylinder 1 needs to be filled with part of liquid material, after the qualified chlorosilane product is filled into the cylinder 1, the volume of the material accounts for about 3% to 5% of the volume of the cylinder 1. The liquid chlorosilane material is located at the bottom of the bottle body close to the bottle valve 2, and the temperature control device is arranged at the upper segment and the lower segment of the cylinder 1 respectively, and is used for heat exchange with the corresponding part of the bottle body.

[0052] In the embodiment, the new cylinder used after passing the factory inspection is used, the bottle valve 2 is normally installed, the volume of the common cylinder 1 is 10L, 47L or 450L, and the cylinder with a volume of 47L is used in the embodiment of the present application. The following is the precondition for passivating and cleaning the cylinder 1: the cylinder 1 in the present application passes the positive pressure and negative pressure pressure maintaining, and the water and oxygen replacement is qualified, and the water and oxygen content is ≤0.1ppm. It should be noted that during the entire passivation process, the pressure of the cylinder during the passivation process is ≤1MPa from the safety point of view.

[0053] In the present application, the temperature control device installed on the cylinder 1 can adopt various heat exchange modes, in a typical embodiment, the present application adopts a heat conduction coil pipe mode, the heat conduction coil pipe is sleeved and fixed at the corresponding position of the cylinder 1, so as to realize the heat exchange with the corresponding part of the cylinder 1, the heat conduction coil pipe is made of metal material with good heat conduction, and a medium such as heat conducting oil is introduced into the heat conduction coil pipe, and a corresponding temperature controller is arranged outside to adjust the oil temperature introduced into the heat conduction coil pipe.

[0054] In an embodiment of the present application, the temperature control device comprises a first temperature control unit 8 located at the lower segment of the inverted cylinder 1 and a second temperature control unit 9 located at the upper segment of the cylinder 2, wherein the heat conduction coil pipe of the first temperature control unit 8 occupies a position of about 1 / 5 of the length of the entire bottle body, and the heat conduction coil pipe of the second temperature control unit 9 occupies a position of about 4 / 5 of the length of the entire bottle body. Figure 2As shown, the first temperature control unit 8 is located at the bottle body position of the gas cylinder 1 close to the cylinder valve 2, and is used for heating the lower section bottle body part of the inverted gas cylinder 1 close to the cylinder valve 2; so as to heat the liquid phase material in the inverted gas cylinder 1 into gas state, with the continuous vaporization of the liquid phase material in the lower part of the gas cylinder (inverted), the gas phase rises, fills the internal space of the gas cylinder 1, and fully contacts with the inner surface of the gas cylinder 1, so as to rapidly carry out passivation at a high temperature, and form a stable passivation film. The preset temperature of the second temperature control unit 9 is lower than that of the first temperature control unit 8, and therefore the heat conduction coil of the second temperature control unit 9 is used for heat exchange through the gas phase raw material of the upper section bottle body and the top space of the inverted bottle body. Since the preset temperature of the second temperature control unit 9 is relatively low, the gas phase material is condensed on the inner wall of the gas cylinder 1, the condensation amount continuously increases, the weight of the liquid bead continuously becomes large, and finally flows downward from the inner wall of the gas cylinder 1 by relying on its own gravity, so as to carry away the trace impurities remaining on the inner wall of the gas cylinder 1 into the lower part of the gas cylinder 1. In the gas cylinder 1, the vaporization and condensation of the material are repeated, and the reciprocating operation is carried out; it needs to be pointed out that the temperature of the second temperature control unit 9 is preferably 5-20℃ lower than that of the first temperature control unit 8.

[0055] In the scheme, the preset temperature of the first temperature control unit 8 is also different with different products filled in the gas cylinder 1, according to the material saturated vapor pressure ≤1MPa, the passivation temperature of electronic grade silicon tetrachloride ≤160℃, the passivation temperature of electronic grade trichlorosilane ≤123℃, and the passivation temperature of electronic grade dichlorosilane ≤95℃; therefore, there is a large difference in the set temperature of the temperature controller among various materials, and the set temperature needs to be set according to the filled product.

[0056] In the scheme, the first temperature control unit 8 is correspondingly provided with a temperature controller I 11, the oil temperature of the heat conduction coil in the first temperature control unit 8 is adjusted through the temperature controller I 11, the second temperature control unit 9 is correspondingly provided with a temperature controller II 12, the oil temperature of the heat conduction coil in the second temperature control unit 9 is adjusted through the temperature controller II 12, and since the second temperature control unit 9 is lower than the first temperature control unit 8 by a certain temperature, the second temperature control unit 9 plays a role in cooling the upper section 200 of the inverted gas cylinder, so that the gas phase material in the internal part is condensed into liquid phase and flows down along the inner wall of the gas cylinder.

[0057] In an embodiment of the present application, a pressure gauge 3 is further arranged, the pressure gauge 3 is installed on the passivation pipeline 10, and is used for detecting the pressure in the passivation pipeline 10; specifically, the range of the pressure gauge 3 is-0.1MPa-2MPa.

[0058] In the scheme, the vacuum pump 4 is connected with the vacuum interface of the passivation pipeline 10, and the vacuum pump 4 is used for carrying out vacuumizing operation on the passivation pipeline 10 and the gas cylinder 1; since the silicon-based electronic gas has strong corrosiveness, in order to protect the equipment, a dry pump is preferably adopted. The vacuum degree of the vacuum pump 4 in the scheme needs to be able to reach 10Pa(A)-100Pa(A).

[0059] In the embodiment of the present application, the protective gas source 5 is connected with the protective gas interface, which is used for supplying the protective gas to the passivation pipeline 10 and the gas cylinder 1 and replacing the passivation pipeline 10. The protective gas source 5 in the present scheme can use high-purity inert gas, and the appropriate packaging gas needs to be selected according to the requirements of the downstream customers. For example, the high-purity inert gas in the present scheme can use nitrogen, argon, and helium. The protective gas source 5 in the present scheme can pressurize the passivation pipeline 10 through the protective gas interface. Since the gas cylinder valve 2 is communicated with the passivation pipeline 10, the gas cylinder 1 can also be pressurized through the protective gas interface, the passivation pipeline 10, and the gas cylinder valve 2. The high-purity inert gas in the present scheme needs to reach the following indexes: the purity of the high-purity inert gas is greater than or equal to 5N, the moisture is less than or equal to 10ppb, the oxygen is less than or equal to 10ppb, and the pressure is 0.5MPa to 1MPa. The replacement effect is ensured.

[0060] In the present scheme, the qualified product tank 6 is used for containing the corresponding chlorosilane qualified product. The qualified product tank 6 is connected with the qualified product interface, which is used for filling the liquid chlorosilane for cleaning and passivation into the gas cylinder 1. The qualified product tank 6 contains the silicon-based electronic special gas product that has passed the detection. The product to be packaged in the gas cylinder 1 is consistent with the corresponding product. The pressure of the qualified product tank 6 is controlled at 0.3MPa to 0.6MPa. The silicon-based electronic special gas product in the qualified product tank 6 can be pressed into the corresponding gas cylinder 1 by the action of the gas pressure.

[0061] In one embodiment of the present application, the waste liquid tank 7 connected with the waste liquid discharge port is used for storing the waste liquid discharged from the gas cylinder 1 after cleaning. After the passivation and cleaning in the gas cylinder 1 are completed, the waste liquid needs to be discharged into the waste liquid tank 7 through the gas cylinder valve 2, the passivation pipeline 10, and the waste liquid discharge port after being cooled. The pressure in the waste liquid tank 7 is controlled at 0.05MPa to 0.2MPa.

[0062] In the present scheme, in order to realize the sequential connection of the gas cylinder 1, the qualified product tank 6, the vacuum pump 4, the protective gas source 5, the waste liquid tank 7, and the pressure gauge 3, the passivation pipeline 10 is arranged, and the gas cylinder interface, the qualified product interface, the vacuum interface, the protective gas interface, the waste liquid discharge port, and the pressure gauge interface corresponding to the above-mentioned devices are arranged on the passivation pipeline 10, so that the whole system is connected. In order to ensure the high-purity property of the system, the pipeline used in the system is a 316L material EP pipeline.

[0063] In order to improve the passivation and cleaning efficiency of the system, a plurality of gas cylinder interfaces can also be arranged on the system according to the actual situation. After a plurality of gas cylinders are connected through the plurality of gas cylinder interfaces, the plurality of gas cylinders 1 can be passivated in parallel, which can meet the demand of simultaneously passivating a plurality of gas cylinders 1.

[0064] The present scheme also provides a passivation method for a steel seamless gas cylinder for silicon-based electronic special gas, and the specific steps are as follows:

[0065] Step one, the gas cylinder 1 is inverted and connected to the passivation system, and the passivation pipeline 10 is qualified for pressure retention;

[0066] Specifically, the gas cylinder valve 2 of the gas cylinder 1 is closed, the passivation system is connected, the entire passivation system is filled with high-purity inert gas, the passivation pipeline 10 is qualified for pressure retention at positive pressure 1 MPa (G) and negative pressure 50 Pa (A), and is put into use. It needs to be pressure retained for 1 h under the corresponding positive pressure or negative pressure. According to the Clapeyron equation, the leakage rate S = (1-P2T1 / P1T2) x 100%, wherein P1 represents the system pressure at the beginning of the test, P2 represents the system pressure after the test, T1 represents the system temperature (K) at the beginning of the test, T2 represents the system temperature (K) at the end of the test, and S < 0.5% is qualified for pressure retention;

[0067] Step two, the passivation pipeline 10 is filled with pressure by the protection gas source 5;

[0068] At this time, the valves on the passivation pipeline 10 are closed, only the protection gas interface and the pressure gauge 3 are connected, the high-purity inert gas is filled into the passivation pipeline 10 to 0.3 MPa-0.6 MPa, the filling is stopped, and then the vacuum is replaced.

[0069] Step three, the passivation pipeline 10 is vacuumed by the vacuum pump 4;

[0070] The vacuum pump 4 is started to reduce the pressure of the passivation pipeline 10 to 50 Pa (A), and the passivation pipeline 10 is replaced once;

[0071] Step four, repeat steps two and three for a predetermined number of times;

[0072] Continue to repeat step two of filling pressure and step three of vacuuming, so as to repeat 3-5 times of replacement, so as to ensure the high-purity property of the passivation pipeline 10 and avoid the pollution caused by water and oxygen;

[0073] Step five, the gas cylinder 1 is vacuumed by the vacuum pump 4;

[0074] The gas cylinder valve 2 and the vacuum pump 4 are opened, the vacuum pump 4 is connected to the inside of the gas cylinder 1 through the passivation pipeline 10 and the gas cylinder valve 2, and the pressure of the gas cylinder 1 is vacuumed to 50 Pa (A).

[0075] Step six, the qualified product tank 6 is sent to the gas cylinder 1 with certain materials;

[0076] Close other valves, open the qualified product interface valve of the qualified product tank 6 and the cylinder valve 2, realize the communication of the qualified product tank 6 with the cylinder 1 through the cylinder valve 2, press the product in the qualified product tank 6 into the cylinder 1, and specifically, the volume of the pressed qualified product is 3%-5% of the volume of the cylinder 1. The pressed product is consistent with the product packaged in the cylinder 1. The required passivation material only accounts for 3%-5% of the volume of the cylinder 1, compared with the normal temperature liquid phase passivation, the efficiency is improved and the required material for single passivation is reduced, the electronic grade product is greatly saved, and the production cost is obviously reduced.

[0077] Step seven, control the first temperature control unit 8 and the second temperature control unit 9 to the preset temperature through the temperature controller according to different materials;

[0078] Open the temperature controller I 11 and the temperature controller II 12 to control the temperature of the heat conducting medium in the heating coil, and select the appropriate heating temperature according to different materials, and take the electronic grade silicon tetrachloride as an example, and at the same time, the safety of the system is considered, the preset temperature of the temperature controller I 11 is set to 80-100 DEG C, and the preset temperature of the temperature controller II 12 is 5-20 DEG C lower than that of the temperature controller I 11.

[0079] The passivation temperature is higher than the normal temperature passivation by 30-50 DEG C, according to the Van't Hoff rule: k(T+10K) / k(T)≈2-4, that is, when the temperature is increased by 10 DEG C, the reaction rate is increased by 2-4 times, under this condition, the passivation efficiency is obviously improved.

[0080] Step eight, the liquid phase material in the lower segment 100 of the inverted cylinder 1 is continuously vaporized, and the gaseous material entering the upper segment 200 of the inverted cylinder is condensed on the inner wall of the cylinder 1, and the vaporization and condensation of the material circulate between the upper and lower segments of the cylinder 1 space; the liquid phase material continuously vaporizes in the lower part of the cylinder (inverted), the gas phase rises and fills the internal space of the cylinder 1, and fully contacts with the inner surface of the cylinder 1, and rapidly performs passivation at a higher temperature to form a stable passivation film. At the same time, because the temperature controlled by the temperature controller II 12 is relatively low, the gaseous material condenses on the inner wall of the cylinder 1, the condensation amount continuously increases, the weight of the liquid bead continuously increases, and finally flows downward from the inner wall of the cylinder by its own gravity, carrying away the trace impurities remaining on the inner wall of the cylinder into the lower part of the cylinder. In the cylinder 1, the vaporization and condensation of the material are repeated.

[0081] Step nine, heat for a certain time, stop heating after the predetermined passivation and cleaning are completed, and use the protective gas source 5 to completely press the material in the cylinder 1 into the waste liquid tank 7 when the temperature of the cylinder 1 decreases to a certain temperature.

[0082] After the cylinder 1 is heated for 24-48 hours, the passivation and cleaning in the cylinder 1 are completed, the temperature controller is controlled to stop heating the cylinder 1, and after the overall temperature of the cylinder 1 is lowered to 30-40°C, the inert gas is used to completely press the materials in the cylinder 1 to the waste liquid tank 7. Specifically, the protection gas interface is connected first, so that the inert gas is filled in the passivation pipeline 10, then the cylinder valve 2 is opened, at this time the inert gas enters the cylinder 1 through the cylinder valve 2, after the cylinder 1 is filled with a certain pressure, the protection gas interface is closed, the waste liquid tank interface is connected, and the materials in the cylinder 1 are completely pressed to the waste liquid tank 7 by the pressure of the inert gas.

[0083] The present scheme significantly improves the passivation temperature, passivation speed and passivation effect of the silicon-based electronic special gas steel seamless cylinder; high-temperature gas phase passivation is realized in the cylinder 1, the gas phase materials condense and gather on the inner wall of the cylinder 1, the liquid beads that become larger and larger rely on their own gravity to flow down, continuously self-flushing the inner wall, forming a stable passivation film on the inner wall of the cylinder 1 while removing residual trace impurities;

[0084] Step ten, the vacuum pump 4 is used to vacuumize the cylinder 1 and the passivation pipeline 10;

[0085] The vacuum pump 4 is started, the cylinder valve 2 is opened, the cylinder is connected with the passivation pipeline 10, the pressure in the cylinder 1 and the passivation pipeline 10 is vacuumized to 50 Pa(A) by the vacuum pump 4, and the cylinder valve 2 is closed.

[0086] Step eleven, the passivation pipeline 10 and the cylinder 1 are pressurized by using a protection gas source;

[0087] The cylinder valve 2 is opened, the high-purity inert gas is pressurized to 0.3-0.6 MPa by connecting the passivation pipeline 10 and the cylinder valve 2 with the passivation pipeline 10,

[0088] Step twelve, repeat steps ten and eleven for a predetermined number of times;

[0089] The vacuumizing step of step ten and the pressurizing step of step eleven are repeated for 3-5 times of replacement; the passivation pipeline 10 and the cylinder 1 are completely replaced.

[0090] Step thirteen, keep the passivation pipeline 10 at a slight positive pressure, and disassemble the cylinder 1 to complete the passivation.

[0091] The pressure of the passivation pipeline 10 is kept at a slight positive pressure of 10-50 kPa to prevent air in the pipeline from entering, and after the cylinder 1 is disassembled, the final passivation is completed, and the product can be filled for sale;

[0092] For the passivation process steps of multiple cylinders 1 connected in parallel, the principle is similar to the above steps, which will not be repeated here.

[0093] Example 1

[0094] according to Figure 1 The process flow is as follows: Cylinder 1 is a 47L cylinder with a water and oxygen content ≤0.1ppm. The filling material is electronic-grade silicon tetrachloride. The temperature controller I11 is set to 100℃, and the temperature controller II12 is set to 90℃. The pressure gauge 3 has a range of -0.1MPa to 1MPa. Vacuum pump 4 is a dry pump with a vacuum degree of 50Pa(A). The high-purity inert gas is helium, with a purity ≥5N, moisture ≤10ppb, and oxygen ≤10ppb. The pressure of the qualified electronic-grade silicon tetrachloride product tank is 0.5MPa, and the pressure of the waste liquid tank 7 is controlled at 0.1MPa. 2.1kg of electronic-grade silicon tetrachloride is introduced into the 47L cylinder, which is 3% of the cylinder volume. The passivation and cleaning time is 24 hours.

[0095] After high-temperature cleaning and passivation, the gas cylinder was filled to 90% of its capacity (47L). After standing for 24 hours at 25℃, its main impurities were tested.

[0096] Comparative Example 1

[0097] The gas cylinders used were 47L cylinders with water and oxygen content ≤0.1ppm. The cylinders, which had not been passivated and cleaned, were filled with the same batch of electronic-grade silicon tetrachloride as in Example 1, with a filling volume of 90% of the 47L cylinder. After standing in an environment of 25°C for 24 hours, their main impurities were tested.

[0098] The contents of Example 1 and Comparative Example 1 are shown in Table 1. The contents of each impurity were detected by ICP-MS.

[0099] Table 1. Impurity content detection data in Example 1 and Comparative Example 1

[0100]

[0101]

[0102] As can be seen from Table 1, after high-temperature cleaning and passivation, the trace impurities remaining on the inner wall of cylinder 1 were thoroughly cleaned, and the quality was close to that of the product in the mother tank, without causing contamination to the product quality. However, cylinder 1 without passivation showed obvious impurity precipitation, which seriously affected the shipment quality of electronic-grade silicon tetrachloride products. Therefore, passivation of cylinder 1 is essential.

[0103] Comparative Example 2

[0104] The cylinder is selected as 47L cylinder, the water and oxygen content of the cylinder is ≤0.1ppm, the normal temperature passivation once is that the 47L cylinder is filled with qualified electronic grade silicon tetrachloride product, the filling volume is 90% of the cylinder, the cylinder is placed horizontally, the passivation is performed by rolling the cylinder for 24h, the cylinder 1 is inverted, the material in the cylinder 1 is completely pressed out, the pressure of the cylinder is pumped to 50Pa(A) by the vacuum pump 4, the filling is performed again, the filling volume is 90% of the cylinder, and the impurity detection is performed after the cylinder is placed at 25℃ for 24h.

[0105] Comparative example 3

[0106] The normal temperature passivation twice is that, on the basis of the normal temperature passivation once in the comparative example 2, the same condition passivation is performed again: the pressure of the cylinder 1 is pumped to 50Pa(A) by the vacuum pump 4, the filling is performed again, the filling volume is 90% of the cylinder, and the impurity detection is performed after the cylinder is placed at 25℃ for 24h, which is the normal temperature passivation twice.

[0107] Comparative example 4

[0108] The normal temperature passivation three times is that, on the basis of the normal temperature passivation twice in the comparative example 3, the same condition passivation is performed again: the pressure of the cylinder 1 is pumped to 50Pa(A) by the vacuum pump 4, the filling is performed again, the filling volume is 90% of the cylinder, and the impurity detection is performed after the cylinder is placed at 25℃ for 24h, which is the normal temperature passivation three times.

[0109] Comparative example 5

[0110] The normal temperature passivation four times is that, on the basis of the normal temperature passivation three times in the comparative example 4, the same condition passivation is performed again: the pressure of the cylinder 1 is pumped to 50Pa(A) by the vacuum pump 4, the filling is performed again, the filling volume is 90% of the cylinder, and the impurity detection is performed after the cylinder is placed at 25℃ for 24h, which is the normal temperature passivation four times.

[0111] Table 2: Impurity content detection data of example 1 and comparative examples 2-5

[0112]

[0113]

[0114] The high temperature passivation sample in table 2 is the same as each condition of example 1, it can be seen from table 2 that the 90% liquid phase electronic grade silicon tetrachloride is filled into the cylinder 1 at normal temperature, the trace impurities remaining in the inner wall of the cylinder can also be cleaned by rolling the cylinder passivation, the effect of four times normal temperature passivation and one time high temperature passivation is equivalent, but in the four times normal temperature passivation, 90% of the material needs to be filled each time, the passivation times is more, the passivation period is long, the operation is complex, and the cost is obviously high.

[0115] Examples 2-4

[0116] The passivation conditions of examples 2-4 are the same as example 1, example 2 (high temperature passivation 1 in table 3) is the sampling after the product in the cylinder is left for 24 hours, example 3 (high temperature passivation 2 in table 3) is the sampling after the product in the cylinder is left for 72 hours, and example 4 (high temperature passivation 3 in table 3) is the sampling after the product in the cylinder is left for 1 week.

[0117] Comparative examples 6-8

[0118] The passivation conditions of comparative examples 6-8 are the same as comparative example 5, comparative example 6 (room temperature passivation 1 in table 3) is the sampling after the product in the cylinder is left for 24 hours after being passivated four times at room temperature, comparative example 7 (room temperature passivation 2 in table 3) is the sampling after the product in the cylinder is left for 72 hours after being passivated four times at room temperature, and comparative example 8 (room temperature passivation 3 in table 3) is the sampling after the product in the cylinder is left for 1 week after being passivated four times at room temperature.

[0119] Table 3: Impurity content detection data of examples 2-4 and comparative examples 6-8

[0120]

[0121]

[0122] As can be seen from table 3, with the increase of the standing time after filling, the impurity level of the product in the cylinder increases to a certain extent, but the passivation film on the inner wall of the cylinder passivated at high temperature is more stable, and almost no impurity is precipitated, the trace impurity continuously precipitates from the inner wall of the cylinder passivated at room temperature, and the cylinder passivated at high temperature is more helpful to the long-term stable and reliable product quality and the delivery of high purity.

[0123] Example 5

[0124] The high temperature passivation 1 in table 4 changes the temperature of temperature controller Ⅰ 111 to 120℃ and the temperature of temperature controller Ⅱ 112 to 110℃, and the other conditions are the same as those of example 1.

[0125] Example 6

[0126] The temperature of temperature controller Ⅰ 111 is 100℃ and the temperature of temperature controller Ⅱ 112 is 90℃, and the other conditions are the same as those of example 1.

[0127] Example 7

[0128] The high temperature passivation 3 changes the temperature of temperature controller Ⅰ 111 to 70℃ and the temperature of temperature controller Ⅱ 112 to 60℃, and the other conditions are the same as those of example 1.

[0129] Example 8

[0130] The temperature of temperature controller Ⅲ 11 is changed to 40℃ and the temperature of temperature controller Ⅱ 12 is changed to 30℃, and other conditions are the same as those in Example 1.

[0131] Example 9

[0132] The temperature of temperature controller Ⅲ 11 and temperature controller Ⅱ 12 are both set to 20℃, and other conditions are the same as those in Example 1.

[0133] Table 4: Impurity content detection data in Examples 5-9

[0134]

[0135] As can be seen from Table 4, as the passivation temperature decreases, the passivation effect decreases obviously, but too high passivation temperature will cause the system pressure to rise, the safety risk increases, and the energy consumption increases, so a suitable passivation temperature can be selected.

[0136] Example 10

[0137] Table 5: High-temperature passivation 1 is passivated and sampled under the passivation conditions in Example 1, and the passivation time is 24h.

[0138] Example 11

[0139] Table 5: High-temperature passivation 2 changes the passivation time to 48h under the other conditions of Example 10.

[0140] Example 12

[0141] Table 5: High-temperature passivation 3 changes the passivation time to 72h under the other conditions of Example 10.

[0142] Example 13

[0143] Table 5: High-temperature passivation 4 changes the passivation time to 12h under the other conditions of Example 10.

[0144] Example 14

[0145] Table 5: High-temperature passivation 5 changes the passivation time to 6h under the other conditions of Example 10.

[0146] Table 5: Impurity content detection data in Examples 10-14

[0147]

[0148]

[0149] As can be seen from Table 5, as the passivation time decreases, passivation and incomplete cleaning occur in the inner wall of the cylinder, and in order to ensure good passivation and cleaning effect, the passivation time needs to be ensured to be 24h-48h, and the passivation effect is not obviously improved and the production efficiency is reduced and the energy consumption is increased when the passivation time is too long.

[0150] Example 15

[0151] The same as the conditions of Example 1, the passivation and filling sampling are carried out under the passivation conditions in Example 1, and the electronic grade silicon tetrachloride filled into the cylinder in high-temperature passivation 1 in Table 6 is 3% of the volume of the cylinder.

[0152] Example 16

[0153] According to the other conditions of Example 15, the difference is that the electronic grade silicon tetrachloride filled into the cylinder in high-temperature passivation 2 in Table 6 is 10% of the volume of the cylinder.

[0154] Example 17

[0155] According to the other conditions of Example 15, the difference is that the electronic grade silicon tetrachloride filled into the cylinder in high-temperature passivation 3 in Table 6 is 1% of the volume of the cylinder.

[0156] Table 6 Impurity content detection data in Examples 15-17

[0157]

[0158]

[0159] As can be seen from Table 6, as the volume of the electronic grade silicon tetrachloride filled during passivation increases, the passivation effect is improved but not obvious, and the filling coefficient of 3% during passivation is reasonable. When the filled material is only 1%, the material vaporization amount is insufficient, and cannot effectively condense and self-clean in the inner wall of the cylinder, and the passivation effect is poor.

[0160] In the description of the present application, it should be understood that the orientations or positional relationships indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0161] In addition, the terms "first", "second", etc. are used herein only to describe different instances, and do not imply or suggest relative importance or a number of the indicated technical features. Thus, the features defined with "first", "second", etc. can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise explicitly specified and limited.

[0162] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting", "fixing" and the like should be understood in a broad sense, for example, can be fixedly connected, or can be detachably connected, or can be integrated; can be mechanically connected, or can be electrically connected or can communicate with each other; can be directly connected, or can be indirectly connected through an intermediate medium; can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise explicitly limited. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0163] In the present application, unless otherwise explicitly specified and limited, the first feature is "on" or "under" the second feature, which can be direct contact between the first and second features, or indirect contact between the first and second features through an intermediate medium. Moreover, the first feature "above", "over" and "on" the second feature can be directly above or obliquely above the first feature, or only indicate that the horizontal height of the first feature is higher than that of the second feature. The first feature "below", "under" and "under" the second feature can be directly below or obliquely below the first feature, or only indicate that the horizontal height of the first feature is less than that of the second feature.

[0164] In the present application, the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine different embodiments or examples described in the present specification and the features of different embodiments or examples, without contradiction.

[0165] The above merely describes preferred embodiments of the present application, and is not intended to limit the present application in any form. Although the present application has been disclosed with the preferred embodiments as above, it is not intended to limit the present application. Any person skilled in the art, without departing from the technical solution of the present application, can make some changes or modifications to the above disclosed technical content to obtain equivalent embodiments with equivalent changes. However, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application, without departing from the technical solution of the present application, shall still fall within the scope of the technical solution of the present application.

Claims

1. A silicon-based electronic special gas with seamless steel cylinder passivation system, characterized by: Comprising The passivation pipeline is provided with a gas cylinder interface, a qualified product interface, a vacuum interface, a protective gas interface and a waste liquid discharge port, and a pressure gauge is arranged on the passivation pipeline for real-time detection of the pressure of the passivation pipeline; a temperature control device is arranged outside the gas cylinder for realizing the reciprocating of the gasification of liquid chlorosilane material in the gas cylinder and the condensation cycle of the gasified material in the gas cylinder; a qualified product storage tank is connected with the qualified product interface for filling the liquid chlorosilane for cleaning and passivation into the gas cylinder; a vacuum pump is connected with the vacuum interface, and the vacuum pump is used for vacuumizing the passivation pipeline and the gas cylinder; A protective gas source is connected with the protective gas interface for supplying and replacing the protective gas of the passivation pipeline and the gas cylinder; a waste liquid tank is connected with the waste liquid discharge port for storing the cleaned waste liquid discharged from the gas cylinder; the gas cylinder is arranged in an inverted vertical manner, and a cylinder valve of the gas cylinder is communicated with the gas cylinder interface for introducing the qualified product into the gas cylinder, pressing out the cleaning waste liquid and replacing the protective gas; The temperature control device comprises a first temperature control unit arranged at a bottle body position of the gas cylinder close to the cylinder valve for heating the lower section bottle body part of the inverted gas cylinder close to the cylinder valve; the liquid phase material is heated to be gaseous in the inverted gas cylinder, and the gas state material fills the internal space of the gas cylinder, and the gas state material contacts with the inner surface of the gas cylinder to form a passivation film; A second temperature control unit is arranged at a bottle body position of the gas cylinder away from the cylinder valve for condensing the gas phase material in the internal part of the upper section bottle body part of the inverted gas cylinder away from the cylinder valve, and the trace impurities remaining in the inner wall of the gas cylinder are removed by the condensed material cleaning the inner wall of the bottle body; the temperature control temperature of the first temperature control unit is greater than that of the second temperature control unit, so that the gasification and condensation of the material in the gas cylinder are reciprocated.

2. The passivation system for a seamless steel cylinder for electronic special gas based on silicon according to claim 1, characterized in that: A temperature controller is further arranged and connected with the first temperature control unit and the second temperature control unit for controlling the temperature of the upper and lower sections of the bottle body of the gas cylinder.

3. The passivation system for a seamless steel cylinder for electronic special gas based on silicon according to claim 1, characterized in that: The gas cylinder is provided with a plurality of gas cylinder interfaces connected in parallel with the passivation pipeline.

4. A method for passivating a seamless steel cylinder for electronic special gases based on silicon, characterized in that, The passivation system of the steel seamless gas cylinder for silicon-based electronic special gas according to any one of claims 1-3 is used, and the passivation method comprises the following steps: Step one, the gas cylinder is connected to the passivation system in an inverted manner, and the passivation pipeline is pressure-qualified, Step two, the passivation pipeline is pressurized by the protective gas source, Step three, the passivation pipeline is vacuumized by the vacuum pump; Step four, steps two and three are repeated for a predetermined number of times; Step five, the gas cylinder is vacuumized by the vacuum pump; Step six, a certain amount of material is sent into the gas cylinder from the qualified product tank; Step seven, the first temperature control unit and the second temperature control unit are controlled to a preset temperature by the temperature controller according to the material; Step eight, the liquid phase material is continuously gasified in the lower section of the inverted gas cylinder, and the gaseous material entering the upper section of the gas cylinder is condensed on the inner wall of the gas cylinder, and the gasification and condensation of the material are reciprocated between the upper and lower sections of the gas cylinder space; Step nine, heating for a certain time, stopping heating after the predetermined passivation and cleaning are completed, and using the protective gas source to completely press the material in the gas cylinder to the waste liquid tank after the temperature of the gas cylinder decreases to a certain temperature. Step ten, using vacuum pump to vacuum the gas cylinder and passivation pipeline; Step eleven, using the protective gas source to charge the gas cylinder and passivation pipeline; Step twelve, repeat step ten and eleven for a predetermined number of times; Step thirteen, keep the passivation pipeline 10kPa-50kPa micro positive pressure, and disassemble the gas cylinder to complete the passivation.

5. The method according to claim 4, wherein the method is characterized by: In step six, the qualified product tank sends the material volume to the gas cylinder, which accounts for 3%-5% of the gas cylinder volume.

6. The method according to claim 4, wherein the method is characterized by: In step seven, the preset temperature of the second temperature control unit is 5-20℃ lower than the preset temperature of the first temperature control unit.

7. The method according to claim 4, wherein the method is characterized by: In step nine, the heating time is 24h-48h.

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