JP4744231B2 - Special material gas supply system and method - Google Patents

Description

The present invention relates to a bulk supply system and a supply method for special material gas. For example, NH ₃ , BCL ₃ , CL ₂ , SiH ₂ CL ₂ , Si ₂ H ₆ , HBr, HF, N ₂ O, C ₃ F _{The present} invention relates to a bulk supply system and a supply method for stably supplying a special material gas for semiconductors represented by ₈ , SF ₆ , WF _{6 and the} like even at a large flow rate.

  The amount of special material gas used in the semiconductor manufacturing process is increasing as the diameter of silicon wafers increases. In addition, demand for compound semiconductor devices represented by digital information home appliances and mobile phone terminals has been increasing year by year without declining. On the other hand, liquid crystal displays have grown remarkably in recent years, and production of liquid crystal TVs is struggling with competition among manufacturers in various countries. Along with this, the consumption of special material gas used in these increases in proportion to the amount of device production, and the flow of special material gas to be supplied has to be increased. Therefore, as a means of consuming a large amount, a large container having a larger internal volume has been used from a 47 liter container generally used conventionally.

Further, special material gases used in the semiconductor manufacturing process include vapor pressures represented by NH ₃ , BCL ₃ , CL ₂ , SiH ₂ CL ₂ , Si ₂ H ₆ , HF, C ₃ F ₈ , WF _{6 and the} like. Low liquefied gas is often used. As for such a liquefied gas, when the gas in the gas phase portion in the container is released to the outside, an amount of the liquefied gas corresponding to the reduced pressure is evaporated from the liquid phase and supplied to the gas phase. Since much of the energy required for this evaporation is taken away from the liquid phase part remaining in the container, the temperature of the liquid will decrease if the container is not provided with heating means, and the supply pressure in the gas phase will eventually decrease. The problem that it becomes impossible to supply the pressure of this occurs.

In view of this, a method of increasing the evaporation amount of the liquefied gas by applying heat from the outer surface of the container to the container using a heating means is generally taken. Examples of the heating means include a hot hot compress, a hot water jacket heater, and the like. Specifically, the bottom of the container is directly heated using a ceramic heater (or a jacket heater or the like) to increase NH ₃ at a large flow rate. A supply method has been proposed. In addition, it is pointed out that it is effective to use fins to increase thermal efficiency (see, for example, Patent Document 1).

Japanese translation of PCT publication No. 2004-527712 (US Pat. No. 6,581412)

  However, in the conventional method of controlling the outer wall temperature of the container to an arbitrary temperature, when it is controlled at a temperature of room temperature or higher, a phenomenon of reliquefaction occurs in the gas supply line after the container, and mist is generated. When the heating amount cannot catch up with the evaporation amount, a bumping phenomenon occurs in the container, and mist is mixed into the gas supply line. Generation of such mist causes fluctuations in flow rate and pressure, making it difficult to maintain the supply pressure. Also, if the target special material gas is corrosive, problems such as corrosion of supply system members, increase of metal impurities and particles will occur, not only reducing the yield of semiconductor devices but also temporarily suspending the process. It becomes necessary to replace the gas system member.

  As for the heating means, the conventional heating source is a method of directly contacting the container, and once the heat is applied to the container, the temperature cannot be easily lowered due to the heat retaining effect of the heater structure. In addition, ceramic heaters are poor in terms of response due to fluctuations in gas flow rate due to their poor rise / fall performance in principle. In addition, it is necessary to attach fins as incidental facilities, which is economically burdensome.

  Furthermore, in order to increase the evaporation amount of the liquefied gas, a hot hot compress or hot water is generally used as a means for warming the container, and the temperature control is performed by attaching a thermocouple to the heater contact portion on the outer surface of the container. The actual situation is that the temperature is controlled to a predetermined temperature (40 ° C. or lower). In the case of such temperature control, responsiveness to a temperature change in the container is poor, and excessive heat (overshoot) may be applied.

  Further, when the gas type filled in the container is a flammable gas, it is necessary to ensure safety in preparation for an unexpected situation due to leakage. In particular, in the heating member installed in the lower part of the container, the surface temperature may exceed 500 ° C., and depending on the gas type, there is a possibility that it will be higher than the ignition point. If such a gas leaks and comes into contact with the heating member, it may be ignited and cause an explosion.

  An object of the present invention is to attach a halogen lamp heater to the bottom of a pressure vessel including a large vessel such as a ton container and perform on-demand heating control to keep the pressure in the vessel constant, thereby It is an object to provide a supply system and supply method for special material gas that stably supplies even a large flow rate while maintaining quality. In addition, depending on the special material gas, it is necessary to further consider the safety against leakage in the unlikely event, and an object is to provide a supply system and supply method for special material gas having such a high safety.

  As a result of intensive studies to solve the above problems, the present inventors have found that the above object can be achieved by the following supply system and supply method for special material gas, and have completed the present invention. .

That is, the present invention is a supply system for a special material gas, a container filled with the special material gas as a liquefied gas, a halogen lamp heater attached to the bottom of the container, and a pressure measurement for measuring the gas phase pressure in the container means, and have a control means for controlling the output of the halogen lamp heater, PT correlation equation showing a correlation between vapor pressure and temperature of the liquefied gas to the control means is input in advance, the container liquefied gas Based on the liquid temperature obtained from the correlation with the saturated vapor pressure, the liquid set temperature corresponding to the set pressure is obtained in advance, and at the time of control operation, it is obtained based on the gas phase part pressure in the container measured by the pressure measuring means. The difference between the measured liquid temperature and the liquid set temperature is obtained, and the heating by the halogen lamp heater is controlled corresponding to the difference, and the gas phase pressure in the container is kept constant. It is characterized in.

By configuring such a system, it is possible to perform on-demand heating control that can appropriately follow the increase and decrease of the flow rate of the special material gas, and mist generated from the container can be prevented in advance. In other words, heating of a gas container by a halogen lamp heater (hereinafter sometimes referred to as “halogen lamp” for short) is on demand because there is no thermal inertia caused by the heating side heat capacity compared to heating by an electric heater or hot water. -It has been found that it is suitable as a heat source that requires heating control. As described above, the temperature of the liquid phase is important in the large flow rate and stable supply of liquefied special material gas. On the other hand, the liquid phase temperature can be obtained accurately by measuring points such as convection and the distance from the vessel wall. It can be difficult. The present inventor has found that the vapor pressure of the liquefied gas, that is, the pressure in the container is an important index as a control target in the supply of the special material gas, and derived from the correlation between the vapor pressure obtained from the physical properties and the temperature. It was found that excellent control is possible by controlling the output of the halogen lamp heater based on the liquid temperature and the liquid set temperature. In particular, as described later, by performing PID control, excellent control without occurrence of the above-described overshoot is possible.

Specifically, when a large amount of liquefied gas is consumed in the process gas used in semiconductors, it is difficult to secure the target flow rate due to the loss of latent heat of vaporization. Heating with a halogen lamp heater was devised as a means to supplement from the outside, and by using this heat source, liquefied gas can be supplied stably even at a large flow rate, and thermal efficiency is reduced compared to conventional jacket heaters etc. It was possible to improve 2 times. It was also found that the dependency on the remaining amount of high-boiling impurities mainly composed of moisture can be eliminated. Therefore, it is possible to provide an excellent supply system for special material gas that can supply the special material gas stably even at a large flow rate.

The present invention is the above-described special material gas supply system, a heating control by the halogen lamp heater, and performs the PID control.

With such a configuration , the pressure in the container is brought close to the actual target value by PI control, and the PID control that adds a differential operation to the change in the supply amount of the material gas or the accompanying liquid phase temperature is used to appropriately follow the change. Time constant control characteristics can be obtained. Therefore, it has become possible to provide an excellent supply system for special material gas that can stably supply special material gas at a large flow rate.

The present invention is the above-described supply system for special material gas, characterized in that the outer surface of the container bottom irradiated by the halogen lamp heater is colored in a color having high heat absorption efficiency.

  The halogen lamp has a quicker response than other heating methods and is non-contact with the heating target, so that the surface treatment of the heating target is easy. The present invention has been able to effectively utilize the advantages of using such a halogen lamp. By coloring the outer surface of the bottom of the container into a color having high heat absorption efficiency, the energy irradiated by the halogen lamp can be efficiently obtained. Since it can be absorbed, the thermal efficiency is further improved and energy saving can be achieved. At the same time, even if the remaining amount of liquefied gas in the container decreases, gas impurities are not concentrated on the liquid phase side, and it is possible to constantly supply high-purity gas stably from the beginning to the end of use. is there. The term “color with high heat absorption efficiency” as used herein refers to a color having a density of gray or higher, which is generally an achromatic color, regardless of whether it is an achromatic color or a chromatic color. For example, black, gray, or a deep color is applicable.

The present invention is the above-described special material gas supply system, the light emitted from the halogen lamp heater, and having a means for focusing the container does not leak to the outside.

  In addition to the above features, the halogen lamp can also concentrate light on a specific part by controlling the optical path. The present invention has been able to effectively utilize the excellent characteristics of such a halogen lamp, and efficiently absorbs the energy irradiated by the halogen lamp by condensing it on the outer surface of the container so as not to leak outside. As a result, the thermal efficiency is further improved and energy saving can be achieved.

  The present invention is the above-mentioned supply system for special material gas, characterized in that the halogen lamp heater is separated from the environmental atmosphere of the container and stored in a housing.

The surface temperature of the halogen lamp heater is 400 ° C. to 500 ° C., which is lower than that of a heating means using an electric resistor, etc., and may be higher than the ignition point depending on the gas type (for example, , SiH ₂ CL ₂ , Si ₂ H _6, etc.). Further, for example, even a gas having no ignition point, such as N ₂ O, may decompose at a high temperature to generate oxygen, exhibit a flame-sustaining property, and promote a fire. The present invention considers such a possibility, and even if gas leaks from the container, the separation lamp does not come into contact with the halogen lamp heater stored in the housing. Therefore, dangers such as ignition can be avoided. It also functions to prevent other abnormal situations due to alteration of leakage gas or possible contamination of halogen lamp heaters.

The present invention is the above-mentioned supply system for special material gas, comprising means for supplying a clean fluid, supplying the clean fluid at a predetermined flow rate into the housing, and setting the pressure higher than the environmental atmosphere of the housing It is characterized by being.

  This is a further utilization of the housing, and the safety of the system can be further ensured by setting the pressure in the housing higher than the atmospheric pressure in which the container is stored. That is, the special material gas leaked into the atmosphere is almost equal to or higher than the atmospheric pressure with respect to the atmospheric pressure, so that diffusion of the leaked gas into the housing can be prevented. Accordingly, it is possible to appropriately prevent the risk of ignition or contamination due to the leaked gas.

  The present invention is the above-mentioned supply system for special material gas, wherein the cleaning fluid is an inert gas.

If an inert gas is introduced as the above-described cleaning fluid, safety is further enhanced. That is, the explosive gas has its explosion range determined depending on the oxygen concentration, and generally the higher the oxygen concentration, the wider the range. The present invention is intended to make the atmosphere inside the casing below the lower explosion limit with an inert gas. For example, the inside of the casing is always purged or sealed with an inert gas such as nitrogen (N ₂ ). The safety can be further increased by keeping It also functions to prevent other abnormal situations due to alteration of leakage gas or possible contamination of halogen lamp heaters.

  The present invention provides the above-mentioned supply system for special material gas, comprising pressure detection means for monitoring the pressure in the housing, introducing the output of the pressure detection means into the control means, and supplying power to the halogen lamp heater; It is characterized by controlling the opening and closing of a valve for supplying a special material gas.

  As described above, the atmosphere inside the housing is an important element for safety of the system. In the present invention, pressure is selected as a monitoring element inside the housing, and the measured value is used as a control target to ensure system safety. When the pressure falls below the set pressure, the supply power to the halogen lamp heater is automatically shut off. Alternatively, a system having a control function for shutting off a gas supply valve is provided. As a result, it is possible to avoid the danger associated with the mixing of leaked gas into the housing and to prevent mist generated from the container.

  The present invention is the above-described supply system for special material gas, characterized in that the housing has a light-transmissive heat-resistant glass in the middle between the halogen lamp heater and the bottom of the container.

  The halogen lamp heater emits infrared rays to heat the bottom of the container. To efficiently extract light from the halogen lamp heater housed in the housing, select a glass with high light transmittance that has a light transmissive glass in the housing between the halogen lamp heater and the bottom of the container. Is preferred. That is, heat energy is efficiently given to the bottom of the container due to the high transmittance, and it is possible to prevent a high temperature due to heating of the glass itself and avoid the risk of ignition on the glass surface. Furthermore, a glass excellent in heat resistance and strength is preferred.

  The present invention provides the supply system for the special material gas, wherein a protective member is provided in the heat-resistant glass disposition portion of the casing, the heat-resistant glass disposition portion is closed when the container is carried in and out, and the halogen lamp It is characterized by opening the heat-resistant glass arrangement portion when in use.

  As described above, the casing plays a role of preventing leakage gas from contacting the halogen lamp heater and ensuring light irradiation from the halogen lamp heater by the light transmissive glass. While the housing itself can have a strong structure, heat-resistant glass is generally vulnerable to mechanical shock. In the present invention, in order to protect this glass, an opening / closing type glass protection member is provided in the casing. By operating the protection member according to the use state of this system, the glass which is vulnerable to mechanical shock is protected. It becomes possible to do.

The present invention is also a method for supplying special material gas, wherein a halogen lamp heater is attached to the bottom of a container filled with the special material gas as a liquefied gas , and the pressure for measuring the gas phase pressure in the container Using a special material gas supply means provided with a measuring means and a control means for controlling the output of the halogen lamp heater, a PT correlation equation indicating the correlation between the vapor pressure of the liquefied gas and the temperature is preliminarily provided in the control means. Based on the liquid temperature obtained from the correlation with the saturated vapor pressure of the liquefied gas in the container, the liquid set temperature corresponding to the set pressure is obtained in advance and measured by the pressure measuring means during the control operation. a liquid temperature obtained based on the container gas phase pressure, obtains the difference of the fluid set temperature, PID control child the heating by the halogen lamp heater in response to the difference By, characterized in that for holding the container gas phase pressure constant.

As described above, the present invention makes it possible to stably supply a special material gas at a large flow rate by effectively utilizing the excellent characteristics of the halogen lamp heater and applying a control method that matches the characteristics. It was possible to provide an excellent supply system for special material gas. In addition, in the research of the present invention, such a special material gas supply method can prevent the generation of mist associated with a large flow rate and improve the heat input efficiency from the outside for maintaining the pressure in the container, thereby saving energy. In addition, it has been found that an increase in gas impurities accompanying a decrease in the remaining amount of liquefied gas in the container can be eliminated. Further, it has been found that such a supply method enables excellent control, and in particular, by performing PID control, it is possible to perform excellent control without occurrence of the above-described overshoot.

  As described above, according to the present invention, in the special material gas supply system, the halogen heater is attached to the bottom of the container filled with gas, and the heater is controlled so as to keep the container internal pressure constant. On-demand heating control that can appropriately follow the increase and decrease is possible, and mist generated from the container can be prevented in advance.

  Further, by adopting a method in which the halogen lamp heater irradiation part has a color with high heat absorption efficiency and the light of the halogen lamp is collected in the container, it is possible to further improve the thermal efficiency and save energy. At the same time, even if the remaining amount of liquefied gas in the container decreases, gas impurities are not concentrated on the liquid phase side, and it is possible to continuously supply high-purity gas stably from the beginning to the end of use. became.

  Furthermore, the safety of this system can be further improved by storing the halogen lamp heater in the housing and purging the inside of the housing. In addition, by providing a light transmissive glass between the casing and the container and providing a protective member for the glass, it is possible to configure a system for simply using light efficiently and safely. .

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic view illustrating a special material gas supply system of the present invention. A container 1 filled with a special material gas, a halogen lamp heater 2 attached to the bottom of the container 1, a means (pressure sensor) 4 connected from the inside of the container 1 through a valve 3 to measure the pressure in the gas phase in the container, And means (AVP controller) 5 for controlling the output of the halogen lamp heater 2 so as to keep the pressure in the container constant. In this figure, it further illustrates as an apparatus provided with a reflector 6 for halogen lamp heater which will be described later.

  The special material gas kept under a certain condition is vaporized inside the container 1 and is supplied to each device of the semiconductor manufacturing process, for example, stably through the valve 3. The supply flow rate can be adjusted with a flow rate controller on the process apparatus side.

  The pressure inside the container 1 is controlled by the AVP controller 5 based on the output of the pressure sensor 4. Specifically, a preset value (corresponding to the liquid set temperature derived from the correlation between the vapor pressure and temperature) and the output of the pressure sensor 4 (the liquid temperature derived from the correlation between the vapor pressure and temperature). By performing PID control using AVP (ALL VAPOR PHASE), which will be described later, while comparing with the above, it is possible to perform very stable control without overshoot.

The container 1 contains a liquefied gas having a low vapor pressure typified by NH ₃ , BCL ₃ , CL ₂ , SiH ₂ CL ₂ , Si ₂ H ₆ , HF, C ₃ F ₈ , WF _{6 and the} like. Although the size of the container 1 depends on the scale of the semiconductor manufacturing process to be used, in the present invention, a pressure vessel having a scale of several hundreds to several thousand L is exemplified as the large container. Specifically, for example, in the case of ammonia, the liquefied gas having an internal pressure of about 0.55 to 0.65 MPaG and a liquid temperature of about 13 to 15 ° C. is supplied at about 300 to 350 L / min (SLM). System.
The special material gas supply system according to the present invention can be applied not only to a bulk supply system using a large container such as a ton container but also to a small or standard high-pressure container of several to several tens of liters. Specifically, a system illustrated in FIG. 2 described later can be given.

  A halogen lamp heater 2 is attached to the bottom of the container 1. Since the halogen lamp heater 2 uses light emitted from the lamp as a heat source, the halogen lamp heater 2 is heated only when it is exposed to light, and heat energy is input almost simultaneously with the switch ON / OFF. Accordingly, overshoot can be suppressed by using a control method described later, which has a faster response than the normal heating method. Further, since the halogen lamp heater 2 and the container 1 are not in contact with each other, there is no heat retention effect by the heater, and the responsiveness is extremely good. In addition, the halogen lamp heater 2 has one of the features that it has higher thermal efficiency than conventional hot-heat compresses due to its characteristics, and is superior in that it is much easier to manage operation than warm water heating. high.

  Further, in order to further utilize the characteristics of the halogen lamp heater 2, the light emitted from the lower part of the container is made into a color having a high light absorption efficiency (for example, black, gray, or dark color), so that white or light color is obtained. Compared with coloring, thermal efficiency is further improved. At this time, it is preferable that such a color with high light absorption efficiency is applied only to a portion where light is emitted. In other words, the heating effect for making the internal pressure of the container 1 constant is preferably only the temperature of the halogen lamp heater 2 to be controlled, that is, the portion irradiated with light. This is because it is preferable to eliminate as much as possible the influence of disturbance from the installation location.

  Furthermore, it is preferable to provide a reflector 6 in the halogen lamp heater 2 in order to efficiently emit light to the target surface. As shown in FIG. 1, the light irradiated from the halogen lamp heater 2 is condensed on the container by the reflector 6 so as not to leak to the outside, so that the irradiation energy is efficiently irradiated on the lower surface of the container 1 and the thermal efficiency is further improved. Can be improved. That is, since the container 2 and the halogen lamp heater 2 are not in contact with each other, the light leaking from the gap between the container and the halogen lamp heater is condensed on the target area at the bottom of the container 1 by using the reflector 6 so that the thermal efficiency is further improved. This can be further improved. The reflector 6 can be disposed so as to cover the halogen lamp heater 2 and the entire irradiation surface, or the reflector 6 having a predetermined curved surface can be attached to the lower part of the halogen lamp heater 2. It is also possible to radiate in a desired direction by selecting a material coated with a reflective film.

  The reflecting plate 6 is not particularly limited as long as it reflects visible light and infrared light. However, considering the workability for covering the container 1 and the halogen lamp to ensure the reflecting function, etc. It is preferable to use a member in which a thin film having a high reflection function such as gold or aluminum is formed on the surface of a member such as metal or resin.

  Further, from the viewpoint of operation, the conventional heat source is integrated, so there is a limit to fine temperature control. However, in the case of the halogen lamp heater 2, a predetermined number of heaters can be installed arbitrarily, Fine control of the temperature is possible by arbitrarily controlling the number of heaters and the output of each heater. Furthermore, even in consideration of safety, a non-contact halogen lamp heater has a merit of high safety as compared with a conventional heat source that directly contacts a container. In terms of cost, it is cheaper than conventional heaters and handling is also easier than in the past.

  The pressure sensor 4 is not particularly limited as long as it has pressure resistance, but from the viewpoint of measurement accuracy, a pressure sensor such as a diaphragm type, a piezo type, or a semiconductor type can be appropriately selected.

  In the present invention, it is possible to provide an excellent bulk supply system for special material gas by using the halogen lamp 2 and the AVP controller 5 instead of the conventional hot hot compress or hot water. With AVP, the correlation between the vapor pressure and temperature of the liquefied gas (PT correlation equation) is input in advance, and PID control between the liquid temperature obtained from the saturated vapor pressure of the liquefied gas in the container and the liquid set temperature is performed. It is a control system that enables on-demand heating.

Specifically, it is controlled by the method illustrated in FIG.
Here, a standard high-pressure vessel (for example, a 47 L vessel) is illustrated, but even if it becomes a large vessel, it can be controlled by the same system.
(1) While measuring the pressure of the special material gas supplied from the high-pressure vessel 1 with the pressure gauge 4 in FIG.
(2) The saturation temperature Tsat inside the high-pressure vessel 1 is converted from the pressure measurement value Ph based on the correlation table 7 (correlation data between vapor pressure and temperature created based on the physical property table), and the AVP controller. Enter 5.
(3) The liquid temperature set value Tsat * is input to the AVP controller 5 in advance. Tsat * can be obtained from the following equation, and Tw indicates the ambient temperature or room temperature of the high-pressure vessel 1.

Tsat * = Tw−ΔT
ΔT = Tw−Tsat
Here, by setting the liquid temperature Tsat in the container to be lower (ΔT) than the room temperature Tw, it is possible to prevent the boiling phenomenon that causes mist generation.
(4) A difference between Tsat and Tsat * is obtained, and heating by the halogen lamp heater 2 is controlled in accordance with the difference. Here, it is preferable that the function of the AVP controller 5 performs on-demand control by PID control. As a result, it is possible to respond with good response to flow rate fluctuations and to quickly feed back the state in the container.

By the above control method,
(1) The amount of gas supply can be increased.
(2) A mist-free state can be achieved by lowering the gas temperature or preventing boiling in the container.
(3) By maintaining a uniform liquid temperature, it is possible to prevent impurities from concentrating on the liquid side.
(4) By maintaining a uniform gas-liquid equilibrium state, the amount of residual liquid can be reduced. That is, the gas in the container can be effectively used until the end.
Thus, it has become possible to provide a bulk supply system for supplying an excellent special material gas that could not be realized by the conventional method.

〔Example〕
Examples and the like specifically showing the contents and effects of the present invention will be described below. In addition, it cannot be overemphasized that this invention is not limited to this Example and evaluation method.

<Evaluation method>
About Examples 1-3, it evaluated about the thermal efficiency of each system based on the following reference | standard.

Thermal efficiency [%] = latent heat of vaporization of test gas [kW] / heater power [kW] x 100 [%]
Here, the latent heat of vaporization (molar unit) of the test gas is obtained from a physical property table. In addition, the heater power is constantly monitored by installing a power meter on the heater power line, and is obtained as power in moles per unit time. Therefore, thermal efficiency can be derived from these two parameters.

<Example 1>
The thermal efficiency in the present invention was evaluated using the bulk supply system for special material gas illustrated in FIG. The dimensions of the (large) container used here are an outer diameter of 609.6 mm, a length of 2,225 mm, and a water volume of 470L. A halogen lamp heater is attached to the bottom of the container. A pressure sensor was attached in the immediate vicinity of the container valve, which is the outlet of the gas phase inside the container, and the pressure in the gas phase inside the container was monitored with this pressure sensor and controlled by AVP. For example, when 250 L of water is put in this container and the thermal efficiency is compared between white and gray at the bottom of the container with the same heater capacity, gray 59% and gray can improve thermal efficiency compared to white 34%. . In a similar experiment using the special material gas ammonia (NH ₃ ), it was confirmed that the thermal efficiency of gray was about 1.7 times that of white. In addition, by attaching a reflector that reflects light leaking outside the container from the gap between the halogen lamp heater and the container, the thermal efficiency can be improved by about 10% compared to the case without the reflector. By adopting these methods, when a halogen lamp heater is used in comparison with a conventional hot-heat compress, the thermal efficiency is improved about twice when NH ₃ is used as a liquefied gas source.

<Example 2>
Outer diameter 788Mm, length 2,495Mm, liquid NH ₃ was filled 500kg large container Mizuuchi volume 930L, was flowed NH ₃ at a flow rate of 300SLM. There are two types of heating sources: a method using a halogen lamp heater to control the pressure in the container with an AVP controller, and a method using a hot water jacket heater at 30 ° C. as a comparative example. Moisture in the gas was measured intermittently from the initial filling amount of 500 kg to the remaining amount of 50 kg. The reason for selecting water is that in the case of liquefied gas, water is a high-boiling component that is easily concentrated on the liquid phase side. The results are shown in FIG. When warm water was used, the water began to rise after the remaining amount of liquid NH ₃ became 200 kg or less. On the other hand, when a halogen lamp heater was used, the moisture concentration did not increase from the initial filling amount to the remaining amount of 50 kg, and was below the detection lower limit of 50 ppb.

<Example 3>
A test on the correlation between the flow rate with respect to elapsed time and the internal pressure of the container was performed using NH ₃ . There are two types of heating methods used in this test: 1) no heating and 2) AVP + halogen lamp heater. The results are shown in FIG. First, the flow rate was 300 SLM, the flow rate was lowered to 200 SLM, and after a certain time, the flow rate was further increased to 300 SLM and maintained for a while. 1) Without heating, the pressure decreased with time, and the flow started to decrease after a while, so the test was stopped after 25 minutes. On the other hand, in 2) AVP + halogen lamp heater, the pressure hardly changed even when the flow rate varied, and the flow rate response was very good.

<Another configuration example of the special material gas supply system according to the present invention>
Next, another configuration example of the special material gas supply system according to the present invention will be described. Specifically, description will be made based on a device having a side surface shown in FIG. 5A and a front surface shown in FIG. In this apparatus, the halogen lamp heater 2 and the reflector 6 having the basic configuration shown in FIG. 1 are housed in a single housing 8 and separated from the environmental atmosphere of the container 1 to ensure system safety. ing. Further, a clean fluid (air) or an inert gas is introduced from the clean fluid inlet 9, and a pressure detection means 10 for monitoring the pressure inside the housing 8 is provided to ensure higher safety. A light-transmissive heat-resistant glass 11 is provided in the housing 8 between the halogen lamp heater 2 and the container 1 to ensure the irradiation of light from the halogen lamp heater 2 to the bottom surface of the container 1 and the environment of the container 1. Ensures separation from the atmosphere.

  Note that FIGS. 5A and 5B show a configuration example in which the container 1 and the housing 8 are housed in yet another frame. In order to prevent the leakage of gas in the container 1 from affecting other systems or devices, the air inside the gantry is exhausted with a fan and kept at a negative pressure, so that no leaked gas stays inside the gantry. It has a simple structure.

  Here, the shape and size of the housing 8 are not particularly limited as long as the halogen lamp heater 2 and the reflector 6 can be accommodated, but in order to prevent the purge efficiency by the clean fluid or the loss of irradiation light, A housing 8 having a shape and size for accommodating the minimum reflector 6 is suitable. In addition, a structure in which the reflector 6 is omitted from a part of the housing 8 and the halogen lamp heater 2 is disposed on the reflective surface of the housing 8 is also possible. In this way, by adopting a structure in which the gas leaked from the container 1 does not directly contact the surface of the halogen lamp heater 2, even if the gas leaks from the container 1, the halogen lamp heater 2 housed in the housing 8. Because there is no contact, the risk of ignition can be avoided.

Here, the clean fluid from the clean fluid inlet 9 is introduced into the housing 8. As the introduction fluid, it is possible to use, for example, air in which the outside air separated from the environmental atmosphere of the container 1 is purified. For example, when the internal volume of the housing is about 300 L, the air volume can be sufficiently purged by setting it to about 3 to 30 L / min. In order to maintain a sealed state by pressurization, a lower purge amount is sufficient. Further, if an inert gas is introduced instead of the introduction of outside air, the safety is further enhanced. Specific examples include N ₂ and argon (Ar).

  Moreover, it is preferable to set the pressure in the housing 8 to be higher than the environmental atmosphere of the housing 8, that is, the atmosphere pressure of the container 1 in FIGS. Thus, the diffusion of the leaked gas into the housing 8, that is, the contact of the leaked gas with the halogen lamp heater 2 can be prevented. Here, it is only necessary that the internal pressure of the housing 8 be maintained at a pressure slightly higher than the atmospheric pressure (several tens to several hundreds mmAq or more), and the clean fluid supply means 9 may be a fan having a blowing function and is constantly purged. Either a mechanism capable of sealing or a mechanism capable of sealing may be used.

  Furthermore, it is also preferable to provide a pressure detection means 10 that can constantly monitor the pressure in the housing, and use it as a safety mechanism and a quality assurance function together with the confirmation of the purge state. That is, the pressure information in the housing 8 is linked to the control function of this system, and the supply power to the halogen lamp heater 2 or the special material gas supply valve 3 is automatically shut off when the pressure is lower than the set pressure. By combining the functions, for example, even when the pressure in the housing 8 becomes atmospheric pressure due to breakage of the heat-resistant glass 11 or the like, the quality of the special material gas to be maintained and supplied is maintained and maintained. Can do. Specifically, when the supply power of the halogen lamp heater 2 is shut off, the heating unit stops and the surface temperature can be reduced below the ignition point, thereby avoiding the danger associated with the leakage gas entering the housing. can do. At the same time, the special material gas supply valve 3 is shut off to prevent mist from being generated due to changes in the heating conditions of the container 1 and to prevent the gas containing the mist from being mixed into the special material gas to be supplied. It is possible to construct a system that can supply special material gas of stable quality. A pressure sensor similar to the pressure sensor 2 can be used as the pressure detection means 10.

Here, the housing 8 preferably has a light-transmissive heat-resistant glass 11 between the halogen lamp heater 2 and the bottom of the container 1. In order to efficiently extract light from the halogen lamp heater 2 housed in the housing 8, the housing 8 has a light-transmissive heat-resistant glass 11 in the middle between the halogen lamp heater 2 and the bottom of the container 1, and light is further emitted. It is preferable to select a glass with high transmittance. That is, if the transmittance is low, the heat energy given to the bottom of the container 1 is lost, so a halogen lamp heater 2 with a large capacity must be prepared. Moreover, since the energy lost when transmitting is converted into energy for heating the heat-resistant glass 11 itself, as a result, the heat-resistant glass 11 itself is heated, which is the original purpose of providing the housing. The risk of the leaked gas coming into contact with a hot surface condition and igniting cannot be avoided. Specifically, the light-transmissive heat-resistant glass 11 used here is excellent in strength and heat-resistant glass 11 having a light transmittance of 90% or more is effective. Further, it is more desirable if the light transmittance is 95% or more. For example, borosilicate heat-resistant glass, quartz glass, sapphire (Al ₂ O ₃ ), and the like can be given.

  Moreover, in this system, the structure which has the protection member 12 for heat-resistant glass 11 protection which is illustrated to FIG. 6 (A) and (B) is preferable. That is, the light-transmissive heat-resistant glass 11 preferably has a small thickness when trying to increase the light transmittance, particularly infrared transmittance, while it becomes weak against mechanical shock when the thickness is small. Therefore, in order to protect the heat-resistant glass 11 of the housing 8 containing the halogen lamp heater 2, an openable / closable protective member 12 is provided, and the protective member 12 is closed when the container 1 is loaded / unloaded. 11, and when the container 1 is completely loaded and the gas is used, the heat-resistant glass 11 can be opened to protect the glass that is vulnerable to mechanical shock.

  Specifically, as shown in FIG. 6 (A), when the container 1 indicated by a broken line is provided, the opening / closing type protective member 12 is opened on both sides of the housing, and the light irradiated from the halogen lamp heater 2 is emitted. The bottom of the container 1 can be irradiated. At this time, the protective member 12 also has a technical effect that it has a function as a reflector that prevents light from diverging between the housing 8 and the container 1 and reduces light loss.

  Further, before the container 1 is carried in or after being transported, as shown in FIG. 6B, the protective member 12 is sealed so as to cover the heat-resistant glass 11, and can be protected from mechanical shocks from the outside. it can. With such a configuration, the heat-resistant glass 11 can be damaged even when the housing 8 is moved alone.

Schematic illustrating the supply system for special material gas of the present invention Explanatory drawing which illustrates the control method by AVP which concerns on this invention Explanatory drawing which illustrates the relationship between the residual amount of liquid NH ₃ in a container and the moisture concentration in gas phase NH ₃ in an embodiment according to the present invention Explanatory view illustrating the relationship between the vapor flow rate _of NH ₃ and the container in the gas phase NH ₃ pressure due to difference in No No heating of the examples according to the present invention Schematic illustrating another configuration of the special material gas supply system according to the present invention. Schematic which illustrates the operation state of the light-transmissive glass protecting member in another configuration example

Explanation of symbols

1 Container 2 Halogen lamp heater 3 Valve 4 Pressure measuring means (pressure sensor)
5 Control means (AVP controller)
6 Reflecting plate 8 Housing 9 Clean fluid inlet 10 Pressure detecting means 11 Heat-resistant glass 12 Protective member

Claims (9)

Container special materials gas is filled as a liquefied gas, a halogen lamp heater that is attached to the bottom of the container, pressure measuring means for measuring a vessel gas phase pressure, and have a control means for controlling the output of the halogen lamp heater And
A PT correlation equation indicating the correlation between the vapor pressure of the liquefied gas and the temperature is input in advance to the control means, and the preset pressure is determined based on the liquid temperature obtained from the correlation with the saturated vapor pressure of the liquefied gas in the container. And a difference between the liquid temperature obtained based on the gas phase pressure in the container measured by the pressure measuring means and the liquid set temperature during the control operation. Correspondingly, the heating by the halogen lamp heater is controlled to keep the gas phase pressure in the container constant . The halogen heating control by the lamp heater, special materials gas supplying system according to claim 1, characterized in that the PID control. 3. The supply system for a special material gas according to claim 1, wherein the outer surface of the bottom of the container irradiated by the halogen lamp heater is colored in a color having high heat absorption efficiency. The supply system for a special material gas according to any one of claims 1 to 3, further comprising means for condensing the light emitted from the halogen lamp heater in the container so as not to leak outside. The halogen lamp heater is separated from the environmental atmosphere of the container and housed in a housing , and a means for supplying a clean fluid is provided, and the clean fluid having a predetermined air volume is supplied into the housing, The supply system for a special material gas according to any one of claims 1 to 4, wherein the pressure is set to be higher than that of the environmental atmosphere. 6. The special material gas supply system according to claim 5, wherein the cleaning fluid is an inert gas. Providing pressure detection means for monitoring pressure in the housing, introducing the output of the pressure detection means into the control means, and controlling the opening and closing of a valve for supplying power to the halogen lamp heater and supplying special material gas; The supply system for a special material gas according to any one of claims 5 and 6 . Wherein the housing, and having an intermediate optical transparency of the heat-resistant glass with the halogen lamp heaters and the container bottom, wherein the housing heat-resistant glass provided portion protection member is provided, heat-resistant glass during loading and unloading of the container The supply system for a special material gas according to any one of claims 5 to 7 , wherein the disposing portion is closed and the heat-resistant glass disposing portion is opened when the halogen lamp heater is used. A halogen lamp heater is attached to the bottom of a container filled with a special material gas as a liquefied gas , and pressure measuring means for measuring the gas phase pressure in the container and control means for controlling the output of the halogen lamp heater are provided. The PT correlation equation indicating the correlation between the vapor pressure of the liquefied gas and the temperature is input in advance to the control means, and the correlation with the saturated vapor pressure of the liquefied gas in the container is used. Based on the liquid temperature obtained, the liquid set temperature corresponding to the preset pressure is obtained in advance, and at the time of control operation, the liquid temperature obtained based on the gas phase part pressure in the container measured by the pressure measuring means, and obtains the difference of the liquid set temperature, by PID controlling the heating by the halogen lamp heater in response to the difference, to hold the container gas phase pressure constant For special materials gas feed wherein the door.

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