Ozone gas supply system

Abstract

The ozone gas supply system (1) of the present invention is provided with an ozone gas supply device (2), a gas introduction line (3), and a mass flow controller MFC1. The ozone gas supply device (2) is capable of generating and supplying ozone gas with an ozone concentration of 80% by volume or more by low-temperature fractionation of ozone gas obtained in an ozone generator (32). The gas introduction line (3) introduces ozone gas from the ozone generator (32) to the ozone gas supply device (2), making it possible to introduce dilution gas to the ozone generator (32). The mass flow controller MFC1 is capable of adjusting the ozone concentration of the ozone gas in the ozone gas supply device (2) by controlling the flow rate of the dilution gas in the gas introduction line (3).

Description

Technical Field

[0001] This invention relates to a technique for rapidly and repeatedly changing the ozone concentration to any ozone concentration or instantaneously increasing the ozone partial pressure in a gas supply system. This gas supply system is used to obtain high-concentration ozone gas with an ozone concentration of 80% by volume or more (hereinafter, "volume%" is referred to as "%"; the same applies in the figures) through low-temperature fractionation. Background Technology

[0002] From the perspective of improving the reaction efficiency of ozone gas and reducing gas costs, processes using high-concentration ozone gas with higher ozone concentrations than those obtained by conventional discharge ozone generators have begun to be widely used (Non-Patent Literature 1, Patent Literature 1 and 2). For example, by increasing the ozone concentration from 210 g / Nm 3 Increased to 1600g / Nm 3 The cost of oxygen is reduced to 1 / 8 of the traditional level, thereby reducing the operating cost of ultra-high concentration ozone generation systems for water treatment by 70% compared to traditional systems.

[0003] On the other hand, considering the manufacturing and operating costs of high-concentration ozone gas, it is desirable to keep the flow rate and concentration at the minimum required to treat the target.

[0004] One method for generating high-concentration ozone gas is an ozone concentration method utilizing the selective adsorption properties of silica gel for polar molecules. This method can only adsorb and concentrate highly polar ozone molecules from an ozone-oxygen mixture with an ozone concentration of approximately 10% obtained through conventional discharge methods, and can be used in fields such as wastewater treatment (general industry) and semiconductor processes.

[0005] The ozone concentration method described above can remove weakly adsorbed oxygen molecules by controlling the pressure after adsorption (vacuum pressure desorption treatment), thereby concentrating ozone to a concentration of over 30%. However, by controlling the desorption treatment time, the concentration can vary from 30% to a maximum of 80%.

[0006] Furthermore, by equipping three adsorption / desorption containers and adjusting the adsorption and desorption (concentration) times in a timely manner, ozone gas with an ozone concentration suitable for the treatment target can be continuously supplied. Existing technical documents Non-patent literature

[0007] Non-Patent Literature 1: Mitsubishi Electric Technology, 91(12)2017 Patent documents

[0008] Patent Document 1: US No. 11123679B2 Patent Document 2: US No. 8409520B2 Summary of the Invention

[0009] The ozone concentration method described above cannot be applied to semiconductor processes that require high-purity ozone gas because even when using high-purity silica gel, the metallic impurities (Cu, Mg, Ni, Fe, Zn, etc.) contained in the silica gel cannot be completely removed at the ppb level. Furthermore, after concentrating the ozone gas in each container to a predetermined concentration, it is impossible to control the ozone concentration until the gas in the container is completely depleted (until complete desorption occurs).

[0010] Furthermore, since the ozone gas supply is carried out by a mass flow controller after compression by a pump in the supply line, the ozone concentration can drop to 10-20% during compression and flow control when the gas flow rate is low.

[0011] Therefore, in vacuum (reduced pressure) environments such as semiconductor processes, the flow rate is relatively low (e.g., tens to hundreds of cc (cm). 3 In processes with ozone supply rates below 1000 ppm, the above-mentioned ozone supply method is inappropriate.

[0012] The present invention was made in view of the technical problem that the object of the present invention is to provide an ozone gas supply system that can supply ozone gas to an ozone utilization system at a variable ozone concentration using minimal equipment configuration.

[0013] Therefore, in one aspect of the present invention, the ozone gas supply system includes: An ozone gas supply device that generates ozone gas with an ozone concentration of more than 80% by volume through low-temperature fractionation of ozone gas obtained in an ozone generator and supplies it. A gas inlet line introduces ozone gas from the ozone generator into the ozone gas supply unit, enabling the introduction of dilution gas into the ozone generator; and The first mass flow controller is capable of regulating the ozone concentration of ozone gas in the ozone gas supply device by controlling the flow rate of the dilution gas in the gas inlet pipeline (3).

[0014] In one aspect of the invention, the ozone gas supply system includes: The gas supply pipeline supplies ozone gas from the ozone gas supply unit to the treatment equipment; Gas emission pipelines that discharge ozone gas from ozone gas supply devices; and A bypass line, which can discharge residual gas introduced into the gas supply line to the gas discharge line before supplying ozone gas from the ozone gas supply device to the gas supply line.

[0015] In one aspect of the invention, the ozone gas supply system further includes: A dilution gas inlet line, which introduces dilution gas into the gas inlet line; and The second mass flow controller can regulate the ozone concentration of ozone gas in the ozone gas supply device by controlling the flow rate of the dilution gas in the dilution gas introduction pipeline.

[0016] In one aspect of the ozone gas supply system of the present invention, there is a gas supply line for supplying ozone gas from an ozone gas supply device to a processing device, wherein the dilution gas inlet line is provided with a dilution gas supply valve, the gas supply line is provided with an ozone gas supply valve, and the dilution gas supply valve is capable of opening and closing synchronously with the ozone gas supply valve.

[0017] In one aspect of the invention, the ozone gas supply system includes a gas recovery line that can return a portion of the ozone gas supplied from the ozone gas supply device to the processing equipment back to the gas supply line.

[0018] In one aspect of the ozone gas supply system of the present invention, a plurality of ozone gas supply devices are provided. When one of the ozone gas supply devices accumulates liquid ozone, the other ozone gas supply device supplies ozone gas.

[0019] In one aspect of the ozone gas supply system of the present invention, a control unit is provided, which is configured to control the flow rate of the diluent gas and the temperature of the container based on the flow rate of the diluent gas, the relationship between the temperature of the container of the ozone gas supply device storing liquid ozone generated by low-temperature fractionation and the ozone concentration of the ozone gas generated by low-temperature fractionation, and the relationship between the flow rate of the diluent gas and the pressure of the container.

[0020] In one aspect of the ozone gas supply system of the present invention, the flow rate of the diluent gas and the temperature of the container are controlled independently.

[0021] In one aspect of the ozone gas supply system of the present invention, the control unit is configured to control the ozone gas supply pressure and ozone gas concentration of the ozone supply device by changing the flow rate or type of diluent gas while maintaining a constant container temperature.

[0022] In one aspect of the ozone gas supply system of the invention, the diluent gas is a gas having a higher vapor pressure than ozone gas and not reacting with ozone gas.

[0023] In one aspect of the ozone gas supply system of the present invention, there is a gas emission line that discharges ozone gas from the ozone gas supply device, and a gas recovery line that can supply a portion of the ozone gas to be supplied to the processing equipment to the gas emission line connected to the gas supply line.

[0024] In one aspect of the ozone gas supply system of the present invention, a dilution gas inlet line introduces dilution gas into the gas inlet line via a heat exchanger.

[0025] In one aspect of the ozone gas supply system of the present invention, a heat exchanger controls the ozone gas supply pressure and ozone gas concentration by changing the temperature of the diluent gas.

[0026] As described above, according to the present invention, an ozone gas supply system can be provided that can supply ozone gas to an ozone utilization system at a variable ozone concentration using minimal equipment configuration. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the ozone gas supply system in Embodiment 1 of the present invention. Figure 2 An operational example of the valve and mass flow controller in Embodiment 1 is shown. Figure 3 This is a schematic diagram of the ozone gas supply system in Embodiment 2 of the present invention. Figure 4 An operational example of the valve and mass flow controller in Embodiment 2 is shown. Figure 5 This is a graph showing the relationship between dilution gas flow rate, container temperature, and ozone concentration inside the container. Figure 6 This is a schematic diagram of an ozone gas supply system as another aspect of implementation method 2. Figure 7 This is a schematic diagram of the ozone gas supply system in Embodiment 3 of the present invention. Figure 8 This is an example of the operation of the valve and mass flow controller in Implementation Method 3. Figure 9 This is a graph showing the relationship between the dilution gas flow rate and the control values ​​of the supply pressure, the supply ozone gas concentration, and the ozone gas flow rate in Implementation Method 3. Figure 10 This is a schematic diagram of the ozone gas supply system in Embodiment 4 of the present invention. Figure 11 This is an example of the operation of the valve and mass flow controller in Implementation Method 4. Figure 12 This is a schematic diagram of an ozone gas supply system as another aspect of implementation method 4. Detailed Implementation

[0028] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0029] [Implementation Method 1] Figure 1 The ozone gas supply system 1 of Embodiment 1 of the present invention, as shown, supplies high-concentration ozone gas with an ozone concentration of 80% or more in real time at a variable ozone concentration. This ozone gas is concentrated through low-temperature fractionation of low-concentration ozone gas obtained, for example, by electrical discharge. Low-temperature fractionation is a method for separating and storing liquid or gaseous ozone by utilizing the vapor pressure difference between ozone and oxygen.

[0030] The ozone gas supply system 1 includes an ozone gas supply device 2, a gas inlet pipeline 3, a gas supply pipeline 4, a gas outlet pipeline 5, and a bypass pipeline 6.

[0031] The ozone gas supply device 2 generates high-concentration ozone gas with an ozone concentration of over 80% by low-concentration ozone gas (e.g., ozone gas with an ozone concentration of less than 20%) supplied from the gas inlet pipeline 3 through low-temperature fractionation, and supplies it to the gas supply pipeline 4.

[0032] The ozone gas supply device 2 includes a container 21, a cold head 22, a refrigerator 23, and a heat insulation part 24.

[0033] Container 21 introduces low-concentration ozone gas from gas inlet line 3 and generates liquid ozone or high-concentration ozone gas through low-temperature fractionation.

[0034] The cold head 22 performs low-temperature fractionation by cooling or heating the container 21.

[0035] The refrigeration unit 23 controls the cooling or heating of the cold head 22.

[0036] Here, in order to achieve the predetermined ozone concentration and supply pressure (pressure value of pressure gauge PG) of ozone gas, based on Figure 5 The relationship between the dilution gas flow rate, the temperature of container 21, and the ozone concentration within container 21, as well as the relationship between the dilution gas flow rate and the pressure of container 21, shown in the mass flow controller MFC1, and the control program controlling the dilution gas flow rate and the temperature of container 21 are installed in the control unit of the ozone gas supply device 2. Specifically, the pre-obtained relationship between the dilution gas flow rate and the pressure of container 21 is crucial for calibrating the display. Figure 5 The curve representing the relationship is valid (this also applies to implementation 2).

[0037] Furthermore, by taking into account the differences in sensitivity (specific heat, conversion factor) between the dilution gas (e.g., oxygen) and the ozone gas in the mass flow controller MFC1, as well as the gas-dependent exhaust velocity of the exhaust pump P0, more precise mixing of the dilution gas and dilution of the ozone concentration of the ozone gas can be achieved. Specifically, by controlling the operation of the mass flow controller MFC1 via the control unit to adjust the flow rate or type of the dilution gas while maintaining a constant temperature in container 21, the supply pressure and concentration of the ozone gas can be arbitrarily adjusted.

[0038] The insulation section 24 insulates the container 21, the cold head 22, and the refrigerator 23. The exhaust pipe 25 is connected to the insulation section 24. The exhaust pipe 25 is equipped with a valve V4, which allows gas to be introduced from the insulation section 24 into the exhaust pump P0.

[0039] The gas inlet line 3 has an inlet pipe 30 that introduces a low concentration of ozone gas into the container 21 of the ozone gas supply device 2. Furthermore, the inlet pipe 30 allows for the appropriate introduction of the dilution gas, as described below, into the ozone generator 32.

[0040] The inlet pipe 30 also includes a regulator 31, an ozone generator 32, a mass flow controller MFC1, and a valve V1.

[0041] Regulator 31 supplies dilution gas to inlet pipe 30 at a predetermined pressure range. The dilution gas is a gas with a vapor pressure higher than ozone gas and that does not react with ozone gas. Examples of dilution gases include oxygen, nitrogen, argon, helium, or mixtures thereof.

[0042] Ozone generator 32 uses known ozone generation methods such as discharge to generate low-concentration ozone gas, for example, ozone gas with an ozone concentration of about 20%.

[0043] The mass flow controller MFC1 corresponds to the first mass flow controller of the present invention, which controls the flow rate of low-concentration ozone gas supplied from the ozone generator 32. Furthermore, the mass flow controller MFC1 can arbitrarily adjust the ozone concentration of the ozone gas by changing the flow rate of the dilution gas in the ozone gas supply device 2. A mass flow controller capable of precisely adjusting the flow rate is used as the mass flow controller MFC1.

[0044] Valve V1 can introduce low-concentration ozone gas from mass flow controller MFC1 into ozone gas supply device 2 (container 21).

[0045] The gas supply line 4 has a supply pipe 40 that supplies ozone gas with a predetermined ozone concentration, drawn into the container 21 by a supply pump P1 through a vacuum, to the treatment equipment 7. The supply pipe 40 is equipped with a pressure gauge PG and a valve V3. The valve V3 is capable of supplying ozone gas from the container 21 to the treatment equipment 7.

[0046] The supply pipe 40 between valve V3 and treatment device 7 is made of electropolished stainless steel, thereby supplying high-concentration ozone gas to treatment device 7, maintaining an ozone concentration of over 80%.

[0047] The gas emission line 5 has an exhaust pipe 50 that supplies ozone gas, drawn from the ozone gas supply device 2 (container 21) by a vacuum pump P0, to the ozone destroyer 8. The exhaust pipe 50 has a valve V2 that allows ozone gas to be introduced from the container 21 into the exhaust pump P0. The gas obtained from the ozone decomposition in the ozone destroyer 8 is supplied to the exhaust system 9.

[0048] The bypass line 6 has a bypass pipe 60 that supplies residual gas between the ozone generator 32 and valve V1 to the gas discharge line 5 before supplying ozone gas from the ozone gas supply device 2 (container 21) to the gas supply line 4. The bypass pipe 60 has a valve V5 that can supply residual gas to the gas discharge line 5.

[0049] Reference Figure 1 and Figure 2 The following describes an operational example (S1 to S11) of Implementation Method 1.

[0050] During the ozone concentration accumulation process in S1, valves V1 and V2 are open, and valves V3 and V5 are closed. Oxygen (or oxygen with less than 1% N2 or Ar added as a diluent to improve ozone generation efficiency) regulated to a predetermined pressure range by regulator 31 is supplied to ozone generator 32. The flow rate of the ozone-oxygen mixture obtained from ozone generator 32 is regulated by mass flow controller MFC1 and supplied to container 21. Inside container 21, it is maintained at a low temperature (e.g., 90K = -183°C) by cold head 22 controlled by refrigerator 23, and the ozone component of the ozone-oxygen mixture accumulates as liquid ozone.

[0051] After a predetermined amount of liquid ozone is stored in container 21, ozone gas with a predetermined concentration, obtained at any vapor pressure, will be supplied to the processing equipment 7 in the ozone gas supply process of S3 to S10 below by controlling the temperature of container 21.

[0052] The higher the flow rate or concentration of high-concentration ozone gas, the higher the operating cost of the treatment process (treatment equipment 7). Therefore, depending on the application, it may be effective to reduce the ozone concentration of high-concentration ozone gas while maintaining the same total pressure and flow rate. In this case, the following steps are performed in sequence.

[0053] For example, in Figure 2In steps S2 to S11, the operation of valves V1, V2, V3, V5, mass flow controller MFC1, and container 21 is controlled. Specifically, at the point in time when the ozone concentration of high-concentration ozone gas changes, the following processes are simultaneously performed: controlling the temperature of the liquid ozone section within container 21 (change in pure ozone gas pressure) and introducing a dilution gas (oxygen) whose flow rate is precisely controlled by the mass flow controller MFC1. In the case of Embodiment 1, the dilution gas is the same gas used for ozone accumulation. The steps from S2 to S11 will be described below.

[0054] In the gas purging process of S2, before diluting the ozone concentration in container 21, valves V1 and V2 are closed and valve V5 is opened. As a result, residual gas in the inlet pipe 30 between ozone generator 32 and valve V1 is vacuumed out via bypass line 6 at a pressure, for example, below 10 Pa. Furthermore, the rapid vaporization of liquid ozone caused by the mixing of residual gas is prevented—because the discharge in ozone generator 32 is adsorbed into the inlet pipe 30 and oxygen is transferred to container 21 (liquid ozone section). Furthermore, the temperature of the dilution gas is stabilized. It should be noted that since the amount of ozone that vaporizes briefly or stably varies depending on the temperature and type (e.g., specific heat) of the dilution gas, the ozone concentration adjusted in processes S3 to S10 is stabilized by presetting the composition and temperature of the dilution gas.

[0055] In the temperature control process of S3, valve V5 is closed and valve V2 is opened. The temperature of container 21 is controlled by the control program, and the target temperature and target pressure of container 21 are controlled so that the ozone concentration of the gas in container 21 is, for example, about 100%.

[0056] In the ozone gas supply process of S4, valve V2 is closed and valve V3 is opened, and ozone gas with an ozone concentration of about 100% is supplied from container 21, which is controlled at the target temperature in S3, to the processing equipment 7 via gas supply line 4.

[0057] In the ozone concentration control process of S5, valves V1 and V2 are opened and valve V3 is closed, allowing dilution gas to be introduced into container 21. Furthermore, by controlling the set concentration and supply pressure of the ozone gas, the flow rate of mass flow controller MFC1 and the set temperature of container 21 are adjusted to the target values.

[0058] In the ozone gas supply process of S6, after confirming that the pressure value of the pressure gauge PG has reached the target pressure (e.g., after 1 minute), valve V2 is closed and valve V3 is opened to start supplying ozone gas of the target concentration (e.g., 40%) to the gas supply line 4.

[0059] In the gas supply concentration setting switching process of S7-S10, due to the changes in the dilution gas flow rate setting and the temperature setting of container 21, valve V3 is closed and valve V2 is opened (S7, S9) for a short period (e.g., 1 minute) until the pressure value of pressure gauge PG stabilizes. As a result, in the processes of S8 and S10, the ozone concentration of the gas supplied to the processing equipment 7 via gas supply line 4 is maintained at a stable target value (e.g., 60%, 100%).

[0060] In the gas supply stoppage process of S11, valves V1, V2, V3 and V5 are closed, thereby stopping the supply of ozone gas from ozone gas supply device 2.

[0061] As described above, according to the ozone gas supply system 1 of Embodiment 1, the concentration of ozone gas supplied to the processing equipment 7 can be arbitrarily varied by a minimum number of pipes and valves.

[0062] Furthermore, the ozone partial pressure (ozone flow rate) can be varied while maintaining a constant total pressure (total flow rate) of the supplied gas. In particular, when using ozone gas as an oxidation source in processes such as MBE (Molecular Beam Epitaxy) or ALD (Atomic Layer Deposition), the ozone concentration (ozone / oxygen partial pressure ratio, flow rate ratio) can be varied in real time while maintaining a constant supply gas flow rate or supply pressure. This allows control over the total pressure and concentration of the ozone-containing gas, enabling the selection of the process point that maximizes ozone gas efficiency. Then, high-purity ozone gas with a high manufacturing cost and a purity of 80% or higher can be used under process conditions that maximize ozone gas efficiency while minimizing operating costs. Furthermore, compatibility with conventional processes using ozone gas is ensured, allowing the use of ozone gas with a concentration of 80% or higher.

[0063] Furthermore, by independently controlling the flow rate of the dilution gas and the temperature of container 21 (vapor pressure of ozone gas), the gas pressure, total gas flow rate, and ozone concentration can be arbitrarily controlled with high reproducibility.

[0064] [Implementation Method 2] exist Figure 3 In the ozone gas supply system 1 of Embodiment 2 of the present invention shown, in aspect 1, a dilution gas inlet line 11 is provided, which independently controls the flow rate of the dilution gas from the gas inlet line 3.

[0065] The dilution gas inlet line 11 has an inlet pipe 110 that introduces the dilution gas into the inlet pipe 30 of the gas inlet line 3.

[0066] The inlet pipe 110 also includes a regulator 31, a mass flow controller MFC2, a valve V5 (1), and a heat exchanger 111. The valve V5 (1) and the heat exchanger 111 are located between the mass flow controller MFC2 and the ozone gas supply device 2.

[0067] The mass flow controller MFC2 is equivalent to the second mass flow controller of the present invention, which can adjust the ozone concentration of ozone gas in ozone gas supply device 2 by controlling the flow rate of dilution gas in dilution gas introduction pipeline 11.

[0068] The diluent gas can be high-purity O2, Ar, N2, etc., which has a higher vapor pressure (boiling point) than ozone gas in the low-temperature region (90K~130K) and does not react with ozone gas.

[0069] The dilution gas promotes the vaporization of liquid ozone according to the constant pressure molar heat [Cal / K·mol]. Even when the temperature of the container 21 of the ozone gas supply device 2 is constant, the introduction of the dilution gas will relatively increase the ozone concentration.

[0070] Furthermore, the low-pressure molar specific heats of O2, N2, and Ar are 7.05, 6.92, and 4.99 Cal / K·mol, respectively. Moreover, under conditions of a container temperature of 100 K and a supply pressure of 5000 Pa, the ozone concentration differs by 5% when diluted with O2 gas and when diluted with Ar gas (for example, the ozone concentration is 24% when diluted with O2 gas and 19% when diluted with Ar gas). Therefore, the ozone concentration can be adjusted within a 5% range by changing the type of diluent gas. Specifically, similar to Embodiment 1, the supply pressure and concentration of ozone gas can be arbitrarily adjusted by controlling the operation of the mass flow controller MFC2 via the control unit under constant temperature conditions in container 21 to change the flow rate or type of diluent gas.

[0071] Furthermore, by controlling the temperature of the dilution gas, the ozone concentration can be adjusted within a range of several percentage points. For example, by changing the temperature of the dilution gas from 25°C to 75°C, the ozone concentration inside the container can be adjusted from 24% to 28%. Specifically, by changing the temperature of the dilution gas through the operation control of the heat exchanger 111 by the control unit, the supply pressure and concentration of the ozone gas can be arbitrarily adjusted.

[0072] In addition, such as Figure 3As shown, by supplying dilution gas to container 21 via heat exchanger 111, the gas temperature inside container 21 can be controlled more stably, the vaporization rate of liquid ozone becomes stable, and the stability of ozone concentration control is improved. In particular, by controlling the gas temperature with high precision (e.g., 50 ± 0.5 °C), even higher precision ozone concentration control can be achieved.

[0073] Reference Figure 3-5 Here is an example of how to implement 2.

[0074] The operation schemes of valves V1-V3, mass flow controller MFC1, and container 21 in Embodiment 2 are basically the same as those in Embodiment 1.

[0075] Specifically, in Embodiment 2, in steps S2 and S5-S8, valve V5(1), which serves as a dilution gas supply valve, is opened. Furthermore, in steps S5 and S6, based on... Figure 5 The relationship between ozone concentration and the flow rate of dilution gas and the temperature of container 21 is shown to set the set flow rate of mass flow controller MFC2. Figure 5 This displays the ozone concentration achievable under conditions of constant supply pressure and flow rate, with oxygen as the diluent gas and a gas temperature of 25°C. Based on the supply pressure (total pressure) and total supply flow rate of the supply gas, ozone gas concentrations over a wide range can be achieved under constant conditions. The delay time represents the stabilization time of the diluent gas flow rate and the stabilization time of the temperature of container 21, typically ranging from 1 to 3 minutes.

[0076] According to Embodiment 2 described above, similar to Embodiment 1, ozone gas can be supplied to the processing equipment 7 at the desired ozone concentration and pressure, regardless of the gas flow rate, gas pressure conditions, and spatial arrangement of the processing furnace. In particular, by providing a dilution gas inlet pipeline 11, the type of dilution gas can be freely selected, and the flow rate of the dilution gas can be controlled independently.

[0077] Furthermore, when the gas flow rate supplied to the processing equipment 7 of the gas supply pipeline 4 is limited and the distance between the processing equipment 7 and the ozone gas supply device 2 is long, it is necessary to supply gas at a certain or higher gas flow rate (velocity) to maintain the ozone concentration.

[0078] therefore, Figure 6 The ozone gas supply system 1 also includes a gas recovery line 12 in the gas supply line 4.

[0079] The gas recovery line 12 has a recovery pipe 120 that recovers a portion of the supply gas from the supply pipe 40 of the gas supply line 4. The recovery pipe 120 has a valve V7 that can return the recovered portion of the supply gas to the exhaust pipe 50 connected to the supply pipe 40 as needed.

[0080] according to Figure 6 The configuration shown allows for the opening of valve V7 as needed during brief transitions accompanying changes in ozone concentration control targets. The supply gas recovered in gas recovery line 12 is then returned to gas supply line 4. This ensures that the correct concentration of ozone gas can be supplied to the treatment unit 7. Furthermore, when the treatment unit 7 and ozone gas supply device 2 are physically separated, or when the gas flow rate is low, the supply gas is circulated back to gas supply line 4 via gas recovery line 12. This suppresses the decomposition of ozone gas during transport and allows for the supply of high-concentration ozone gas to the treatment unit 7.

[0081] [Implementation Method 3] Figure 7 The ozone gas supply system 1 in Embodiment 3 of the present invention shown is equipped with a valve V6 in the gas supply line 4 of Embodiment 2. The valve V6 can intermittently supply ozone gas from the ozone gas supply device 2 to the processing device 7 in sync with the operation of the valve V5 (1).

[0082] That is, by intermittently and rapidly opening and closing valve V6 during the supply of high-concentration ozone gas to the treatment device 7, while maintaining the temperature of the container 21 storing liquid ozone (e.g., 125K), dilution gas is additionally introduced into the container 21 from the dilution gas inlet line 11. This increases the total pressure of the gas supplied to the treatment device 7 and the partial pressure of ozone. Therefore, the gas flow rate (velocity) increases briefly, and the treatment performance of ozone introduction can be achieved in a short time. Furthermore, significant performance improvements (oxidation, washing, film formation) are achieved through the synchronized operation of valves V5(1) and V6.

[0083] Reference Figure 8 Here is an example of how to implement 3.

[0084] The operating sequence of valves V1-V3, V5(1), mass flow controller MFC1 and container 21 is basically the same as in embodiment 2.

[0085] In the ozone concentration accumulation process of S1, the required amount of liquid ozone is stored in container 21.

[0086] In the gas purging process of S2, valves V2 and V5 (1) are opened, a constant value is set by the mass flow controller MFC2, and dilution gas is introduced into the dilution gas inlet line 11 by evacuating the system using the exhaust pump P0. As the dilution gas, a gas with a higher vapor pressure (boiling point) than ozone gas and a smaller reaction rate constant with ozone gas is desired. For example, nitrogen, argon, and oxygen are suitable.

[0087] In the temperature control process of S3, the temperature of container 21 is adjusted to achieve the desired ozone partial pressure (e.g., 0.1 atmospheres at 130K), and valve V3 is opened. Then, ozone gas is filled into the supply pipe 40 of gas supply line 4 until valve V6, which acts as the ozone gas supply valve, is activated, and the process enters a standby state. Simultaneously, the mass flow controller MFC2 of dilution gas introduction line 11 receives instructions regarding the desired amount of dilution gas introduced.

[0088] In the ozone gas supply process of S4, a signal synchronized with the opening and closing command signal of valve V6 is output from the processing device 7 to valve V5. Thus, when the processing device 7 needs ozone gas (when valve V6 is open), valve V5 opens, and ozone gas is supplied to the processing device 7 along with dilution gas.

[0089] Figure 9 The diagram illustrates the changes in supply pressure, ozone gas concentration, and ozone gas supply flow rate as the flow rate of the diluent gas increases in Embodiment 3. Although the ozone gas concentration decreases from 90% (vertical axis value 0.9) to a minimum of 30% (vertical axis value 0.3) by introducing the diluent gas, the supply pressure (total pressure) increases from 0.1 atmospheres to a maximum of 0.9 atmospheres, and the ozone gas supply flow rate also increases by approximately 2.5 times. In other words, under constant temperature conditions in container 21, the heat introduced by the diluent gas promotes the vaporization of liquid ozone gas, resulting in a rapid increase in the ozone gas quantity. Figure 9 The supply pressure has increased (from 2.5 times to 2.5 times). Figure 9 (The supply pressure is increased by 9 times). Furthermore, by increasing the supply pressure, even if the gas supply pipeline 4 is long (e.g., supply pipe 40 is over 10 meters), high-concentration ozone gas can be supplied to the treatment system (treatment equipment 7) in a short time. In particular, this contributes to the high efficiency of processing within a system where the high-concentration ozone gas supply time is short (increasing productivity and ozone utilization efficiency).

[0090] According to Embodiment 3 described above, by introducing a dilution gas separately into a container 21 maintained at a predetermined controlled temperature, the heat of the dilution gas (the difference between the gas temperature and the container temperature × the introduced gas × specific heat) promotes the vaporization of liquid ozone within the container 21. This results in a momentary increase in the supply pressure (total pressure). In particular, unlike Embodiments 1 and 2, since temperature control of the container 21 is not required, it can be effectively applied to processes requiring instantaneous response, especially those requiring intermittent high ozone pressure, such as atomic layer deposition (ALD) processes. Furthermore, because the total pressure of the supply gas and the ozone gas pressure increase momentarily, it can be particularly effective in situations where the ozone gas supply pipe is long or the pressure loss is large (e.g., where devices such as valves or filters with low CV values ​​are present).

[0091] [Implementation Method 4] Figure 10 The ozone gas supply system 1 of Embodiment 4 shown has a valve control function that can continuously change the ozone concentration, as in Embodiments 1 and 2, or a valve control function that can operate synchronously with valve V6 in Embodiment 3. Thus, ozone gas can be continuously supplied from the ozone gas supply device 2 to the processing equipment 7 with a variable ozone concentration and a variable dilution rate.

[0092] The ozone gas supply system 1 has multiple ozone gas supply devices 2 for storing liquid ozone, and includes a gas inlet line 3, a gas supply line 4, and a gas outlet line 5 in embodiments 1 and 2 of the multiple systems. Figure 10 The ozone gas supply system 1 shown has ozone gas supply devices 2(1) and 2(2) as multiple ozone gas supply devices 2, and has a dual-system gas inlet line 3, a gas supply line 4 and a gas outlet line 5.

[0093] Valves V1(1), V2(1), V3(1), V4(1) and V5(1) correspond to ozone gas supply device 2(1), and valves V1(2), V2(2), V3(2), V4(2) and V5(2) correspond to ozone gas supply device 2(2).

[0094] Reference Figure 10 and Figure 11 Here is an example of how to implement 4.

[0095] The valve types, mass flow controllers MFC1 and MFC2, and the operation sequence of the containers 21(1) and 21(2) of the ozone gas supply devices 2(1) and 2(2) in Embodiment 4 are basically the same as those in Embodiments 1 and 2.

[0096] Specifically, for example, when a container 21(1) in an ozone gas supply device 2(1) stores liquid ozone, a container 21(2) in another ozone gas supply device 2(2) supplies ozone gas, thereby continuously supplying ozone gas of any ozone concentration (e.g., 40%, 60%) to the treatment device 7.

[0097] Furthermore, in, for example Figure 11 In the gas concentration switching process of S6, S7, and S6, the concentration and pressure of the ozone gas to be supplied can be changed at any time through the flow control of mass flow controllers MFC1 and MFC2 and the temperature control of containers 21(1) and 21(2).

[0098] According to Embodiment 4 described above, ozone gas can be supplied continuously for 24 hours, and the ozone concentration can be changed and controlled at any time. Furthermore, continuous supply is possible when only the ozone gas concentration is variable, provided that the total pressure and total flow rate of the supplied gas are constant. Additionally, similar to Embodiment 3, by synchronizing the valves V5(1) and V5(2) used for diluting the gas with the valve V6 on the processing device 7 side, ozone gas can be supplied under high pressure in a discontinuous (pulsed) manner.

[0099] also, Figure 12 Another aspect of the illustrated embodiment 4 is... Figure 6 Another aspect of the illustrated embodiment 2 similarly includes gas recovery lines 12(1) and 12(2). Gas recovery lines 12(1) and 12(2) correspond to ozone gas supply devices 2(1) and 2(2), respectively.

[0100] The gas recovery line 12(1) has a recovery pipe 120(1) that recovers a portion of the supply gas from the supply pipe 40 of the gas supply line 4. The recovery pipe 120(1) has a valve V7(1) that can return a portion of the supply gas to the exhaust pipe 50(1) connected to the supply pipe 40 as needed.

[0101] The gas recovery line 12(2) has a recovery pipe 120(2) that recovers a portion of the supply gas from the supply pipe 40 of the gas supply line 4. The recovery pipe 120(2) has a valve V7(2) that can return a portion of the supply gas to the exhaust pipe 50(2) connected to the supply pipe 40 as needed.

[0102] according to Figure 12 The method shown allows for the supply of gas from ozone gas supply devices 2(1) and 2(2) to the treatment device 7 under more flexible ozone gas pressure, flow rate, and concentration conditions.

[0103] Specifically, while ozone gas can be supplied continuously for 24 hours, during transition periods caused by changes in the ozone concentration control target, the supplied gas is returned to the gas supply line 4 via gas recovery lines 12(1) and 12(2). This ensures that an accurate concentration of ozone gas is always supplied to the treatment unit 7. Furthermore, when the treatment unit 7 and the ozone supply source are physically separated, or when the gas flow rate is low, the supplied gas is circulated back to the gas supply line 4 via gas recovery lines 12(1) and 12(2). Therefore, a high concentration of ozone gas can be supplied to the treatment unit 7 while suppressing the decomposition of ozone gas during transport.

Claims

1. An ozone gas supply system, comprising: An ozone gas supply device generates ozone gas with an ozone concentration of more than 80% by volume through low-temperature fractionation of ozone gas obtained in an ozone generator and supplies it. A gas inlet line introduces ozone gas from the ozone generator into the ozone gas supply device, enabling the introduction of dilution gas into the ozone generator. The gas supply pipeline supplies ozone gas from the ozone gas supply unit to the treatment equipment; The gas emission pipeline discharges ozone gas from the ozone gas supply device; A bypass line, which can discharge residual gas introduced into the gas supply line to the gas discharge line before supplying ozone gas from the ozone gas supply device to the gas supply line. The first mass flow controller is capable of regulating the ozone concentration of ozone gas in the ozone gas supply device by controlling the flow rate of dilution gas in the gas inlet pipeline. and The control unit is configured to control the flow rate of the diluent gas and the temperature of the container based on the relationship between the flow rate of the diluent gas detected by the first mass flow controller, the temperature of the container of the ozone gas supply device storing liquid ozone generated by cryogenic fractionation and the ozone concentration of the ozone gas generated by cryogenic fractionation, and the relationship between the flow rate of the diluent gas and the pressure of the container. The bypass line is configured to supply residual gas between the ozone generator and a valve that allows ozone gas to be introduced from the first mass flow controller into the ozone gas supply device.

2. The ozone gas supply system according to claim 1 further includes: A dilution gas inlet line, which can introduce dilution gas into the gas inlet line; and The second mass flow controller can regulate the ozone concentration of ozone gas in the ozone gas supply device by controlling the flow rate of the dilution gas in the dilution gas introduction pipeline.

3. The ozone gas supply system according to claim 2, wherein it includes a gas supply line for supplying ozone gas from the ozone gas supply device to the treatment equipment. Among them, dilution The gas inlet line is equipped with a dilution gas supply valve. The gas supply line is equipped with an ozone gas supply valve, and The dilution gas supply valve can open and close synchronously with the ozone gas supply valve.

4. The ozone gas supply system according to claim 2, in, The dilution gas inlet line introduces the dilution gas into the gas inlet line via a heat exchanger.

5. The ozone gas supply system according to claim 4, in, The heat exchanger controls the supply pressure and concentration of ozone gas by changing the temperature of the diluent gas.

6. An ozone gas supply system, comprising: An ozone gas supply device generates ozone gas with an ozone concentration of more than 80% by volume through low-temperature fractionation of ozone gas obtained in an ozone generator and supplies it. A gas inlet line introduces ozone gas from the ozone generator into the ozone gas supply device, enabling the introduction of dilution gas into the ozone generator. The gas supply pipeline supplies ozone gas from the ozone gas supply unit to the treatment equipment; A gas recovery line that can return a portion of the ozone gas supplied from the ozone gas supply unit to the treatment equipment back to the gas supply line; The first mass flow controller is capable of regulating the ozone concentration of ozone gas in the ozone gas supply device by controlling the flow rate of dilution gas in the gas inlet pipeline. The control unit is configured to: control the flow rate of the diluent gas and the temperature of the container based on the relationship between the flow rate of the diluent gas detected by the first mass flow controller, the temperature of the container of the ozone gas supply device storing liquid ozone generated by cryogenic fractionation and the ozone concentration of the ozone gas generated by cryogenic fractionation, and the relationship between the flow rate of the diluent gas and the pressure of the container; and The gas emission pipeline discharges ozone gas from the ozone gas supply device. The gas recovery pipeline is capable of returning a portion of the ozone gas from the gas supply pipeline to the gas emission pipeline.

7. An ozone gas supply system, comprising: An ozone gas supply device generates ozone gas with an ozone concentration of more than 80% by volume through low-temperature fractionation of ozone gas obtained in an ozone generator and supplies it. A gas inlet line introduces ozone gas from the ozone generator into the ozone gas supply device, enabling the introduction of dilution gas into the ozone generator. The gas supply pipeline supplies ozone gas from the ozone gas supply unit to the treatment equipment; A gas recovery line that can return a portion of the ozone gas supplied from the ozone gas supply unit to the treatment equipment back to the gas supply line; The first mass flow controller can adjust the ozone concentration of ozone gas in the ozone gas supply device by changing the flow rate of the dilution gas in the gas inlet pipeline. and The control unit is configured to control the flow rate of the diluent gas and the temperature of the container based on the flow rate of the diluent gas detected by the first mass flow controller, the relationship between the temperature of the container of the ozone gas supply device storing liquid ozone generated by low-temperature fractionation and the ozone concentration of the ozone gas generated by low-temperature fractionation, and the relationship between the flow rate of the diluent gas and the pressure of the container. The gas emission pipeline discharges ozone gas from the ozone gas supply device. The gas recovery pipeline is capable of returning a portion of the ozone gas from the gas supply pipeline to the gas emission pipeline. It is equipped with multiple ozone gas supply devices. When one of the ozone gas supply devices accumulates liquid ozone, the other ozone gas supply device supplies ozone gas.

8. The ozone gas supply system according to any one of claims 1, 6, and 7, in, The flow rate of the dilution gas and the temperature of the container are controlled independently.

9. The ozone gas supply system according to any one of claims 1, 6, and 7, in, The control unit is configured to control the ozone supply pressure and ozone concentration of the ozone supply device by changing the flow rate or type of diluent gas while maintaining a constant container temperature.

10. The ozone gas supply system according to any one of claims 1, 6, and 7, in, Diluent gas is a gas that has a higher vapor pressure than ozone gas and does not react with ozone gas.

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