JP4899451B2 - Ozone generator - Google Patents

Description

  The present invention relates to an ozone generator that can supply high-concentration ozone gas concentrated by liquefying ozone gas, and in particular, in an apparatus that can supply high-concentration ozone gas while generating liquid ozone, the temperature of the ozone chamber is adjusted. It is related with the structure of the temperature control part to perform.

In recent years, the use of ozone (element symbol: O ₂ ) has been developed in various fields including water and sewage treatment using its strong oxidizing power. In particular, in the field of manufacturing semiconductor devices, application to Si wafer cleaning and TEOS-CVD (Tetra Ethyl Ortho Silica-Chemical Vapor Deposition) is being studied. Si wafer cleaning uses ozone water in which ozone gas is dissolved in pure water as a cleaning solution, and it has been announced that heavy metals and organic substances on Si wafers can be removed by using it together with dilute hydrofluoric acid aqueous solution (non-patent document) 1). TEOS-CVD is used to form an interlayer insulating film when a semiconductor element is formed into a multilayer wiring, and is characterized in that the unevenness of the wafer surface due to the electrodes can be planarized by the insulating film. It has been reported that the planarization performance is improved by adding ozone to the TEOS-CVD (Non-patent Document 2).

  These are examples using ozone gas with a relatively low concentration of about 10%, but by using ozone gas with a relatively high concentration of 80% or more, there is a possibility of a new application that could not be considered by conventional ozone gas usage. Has begun to be pointed out. As an example, there is an oxide film formation of a Si semiconductor disclosed in JP-A-8-335576. According to this publication, it is possible to form an oxide film at a relatively low temperature, which is impossible with the conventional thermal oxidation method, and to form a high-quality oxide film with less suboxide layer and defect structure. Has been.

  By the way, a silent discharge system is generally used to generate ozone gas. This generates a mixed gas of ozone and oxygen from oxygen gas by electric discharge. Due to the limit of generation efficiency and danger of explosion, it is difficult to generate ozone gas of about 10% by volume or more under normal temperature and pressure. It was. Therefore, Patent Document 1 (Japanese Patent Publication No. 5-17164) introduces a method of generating high-concentration ozone gas of 80% or more by once liquefying the generated ozone gas and then vaporizing it.

  In the method of liquefying ozone gas in Patent Document 1, only ozone gas is liquefied by the difference in vapor pressure between ozone and oxygen. For example, at 1 atmosphere, the boiling point of ozone is 161K, but the boiling point of oxygen is 90K. Therefore, if it is cooled to a temperature of 90K or more and less than 161K, most of ozone is in a liquid state and most of oxygen is in a gaseous state, so that only ozone can be separated as a liquid. Actually, since it is handled under reduced pressure conditions for safety against explosive properties of high-concentration ozone, the separation conditions are determined by the difference between the vapor pressures of ozone and oxygen under the temperature and pressure conditions. For example, when considering a case where the temperature is 90K and the pressure is 10 mmHg (= 13.3 hPa), the vapor pressure of ozone is almost 0 mmHg (= 0 Pa) at 90K, but oxygen is about 690 mmHg (= 918 hPa), and only ozone is under this condition. Liquefied.

  However, in the production of the liquid ozone, it is necessary to switch the valve between the generation of liquid ozone and the supply of gaseous ozone, and it is impossible to supply high-concentration ozone gas while generating.

  In order to perform continuous supply of high-concentration ozone gas, there is one in which a multi-bessel method is adopted, such as an ozone generator disclosed in Patent Document 2 (Japanese Patent Laid-Open No. 2001-133141). According to this multi-vessel type ozone generator, it is possible to continue supplying concentrated ozone from one ozone chamber and to generate liquid ozone in the remaining ozone chambers in parallel.

  In the multi-vessel system, temperature control is easy because each ozone chamber is provided with an individual cold head or the like. However, since this method is a divided structure, the cold head itself needs to be an individual structure. In addition, it is necessary to provide piping from the refrigerator to each cold head through a separate path, which increases the size and cost of the apparatus.

Therefore, there is an ozone generator disclosed in Patent Document 3 (Japanese Patent Laid-Open No. 2003-20209). FIG. 4 is a schematic configuration diagram of the ozone generator. The ozone generator 40 includes a single cold head 41, a cooling metal block 43 that is thermally coupled to the ozone chamber 42, and a variable thermal resistance that thermally connects the cooling metal block 43 and the cold head 41. And a control device 44. The cold head 41 introduces heat from the refrigerator 45. The cold head 41 is provided with a plurality of variable thermal resistance control devices 44. A cooling metal block 43 is connected to each variable thermal resistance control device 44. Each cooling metal block 43 is provided with an ozone chamber 42. The cooling metal block 43 is provided with a heater, and the power supplied to the heater and the thermal resistance of the variable thermal resistance control device 44 are individually controlled, thereby reducing the influence of heat conduction to the cold head 41 side. The temperature of the ozone chamber 42 is individually controlled. According to this configuration, only one cold head 41 needs to be provided, and piping from the refrigerator 45 to the cold head 41 need only have a single path. In addition, the individual temperature control of the ozone chamber is facilitated compared to the configuration of the ozone generator of Patent Document 2.
Electronic Materials March 1999, pp. 13-18 Jpn. J. et al. Appl. Phys. Vol 32 (1993) pp. L110-L112 JP 5-17164 JP 2001-133141 A JP2003-20209

  The ozone generation apparatus of Patent Document 3 includes a single cold head 41, a plurality of cooling metal blocks 43 for thermally coupling with the ozone chamber 42, and the cold head 41 and the cooling metal block 43. By interposing the variable thermal resistance control device 44 between them, the temperature of each ozone chamber 42 can be individually controlled according to each step of ozone supply, disposal and accumulation in the ozone chamber 42. In addition, the temperature of each ozone chamber 42 can be individually controlled according to the steps of supplying, discarding, and accumulating ozone in the ozone chamber 42. In addition, since only one cold head 41 is required, the apparatus can be reduced in size and cost as compared with the conventional structure. In addition, individual temperature control of the ozone chamber 42 is facilitated.

  However, the structure of the ozone generation unit, which can be said to be the heart of the liquid ozone generation device, in particular, each configuration between the cold head 41 and the cooling metal block 43 has a special shape and has a mechanical movable part. For example, it is not a simple configuration, and further downsizing is an obstacle.

  This invention is made | formed in view of the above situation, The objective is to provide the ozone production | generation apparatus which can further reduce in size and cost by making the structure of an ozone production | generation part into a simpler structure.

Therefore, an ozone generator according to claim 1 includes a heat conductor thermally connected to the refrigerator and a plurality of ozone chambers having a variable thermal resistance control device thermally connected to the heat conductor. , the heat conductor is formed in a plate shape main surface is a rectangle with made of a metal material, the major surface the said upward direction of the heat conductor plurality of variable thermal resistance control apparatus of the heat conductor The variable thermal resistance control device is individually supported by the thermal conductor by a metal support member, and the variable thermal resistance control device is fixed to the support member. It is characterized by comprising a plate-like stage portion and a plate-like support portion that supports the stage portion and is connected to the end surface on the long side of the heat conductor .

  The ozone generator according to claim 2 is the ozone generator according to claim 1, wherein the refrigerator is thermally connected in the vicinity of the short side of the lower surface of the heat conductor.

According to a third aspect of the present invention, there is provided the ozone generation apparatus according to the first or second aspect , further comprising a storage unit that stores the thermal conductor and the variable thermal resistance control device .

According to the invention of claim 1 to 3, wherein a plurality of variable thermal resistance controlling device to the heat conductor main surface is formed in a rectangular with made of a metal material is provided on each of the variable thermal resistance controlling device Since the ozone chambers are thermally connected, it is possible to control the temperature of a plurality of ozone chambers by a single refrigerator without using a special shape and configuration of a refrigerator, a cold head, or the like. . Furthermore, since the support member that supports the variable thermal resistance control device on the heat conductor is made of a metal plate-like member, the heat transfer efficiency between the heat conductor and the variable thermal resistance control device is increased, and the ozone chamber The impact on the surrounding devices due to the vibrations is further mitigated.

  In particular, according to the invention of claim 2, the refrigerator is thermally connected in the vicinity of the short side of the lower surface of the heat conductor, so that a space is secured below the ozone chamber, and the space is It can be used effectively. In addition, the impact on peripheral devices due to the vibration of the ozone chamber is reduced.

Further, according to the invention described in claim 3 , since a plurality of vacuum heat insulating containers storing the ozone chamber are in the form of a unit integrated with the storage unit, the plurality of units are used, Can be arbitrarily mass-produced. Further, since the heat conductor and the variable thermal resistance control device are isolated from the outside air by the storage unit, waste of heat energy can be suppressed.

As described above, according to the first to third aspects of the present invention, the configuration of the ozone generation unit becomes a simpler structure, and the ozone generation device can be reduced in size and cost.

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

(Example 1)
FIG. 1 is a schematic view showing an ozone generator according to an embodiment of the present invention.

As shown in FIG. 1, the ozone generator 1 includes a heat conductor 3 that is thermally connected to the refrigerator 2 and a variable thermal resistance control that thermally connects the heat conductor 3 and the ozone chamber 4. Device 5.

  The heat conductor 3 is made of a metal material and, as is apparent from the shapes shown in FIGS. 1, 2A and 2B, the upper surface 31 and the lower surface 32 which are main surfaces are rectangular plates. It is formed in a shape. On the upper surface 31 of the heat conductor 3, a plurality of variable heat resistance control devices 5 are arranged in series as variable heat resistors. A metal having excellent thermal conductivity is used as the metal material. Examples of the metal include those containing, as a main component, any one of copper, aluminum, brass, iron, titanium, stainless steel, silicon, and the like.

The refrigerator 2 is thermally connected to the heat conductor 3 via the cold head 11 . As shown in FIG. 1, the heat conductor 3 is connected to the cold head 11 in the vicinity of the short side of the lower surface 32 so that heat supplied from the refrigerator 2 can be introduced.

  The ozone chamber 4 temporarily stores ozone generated by an ozonizer (not shown). The ozone chamber 4 is made of a known material that is not corroded by ozone. The ozonizer is not particularly limited as long as it can generate ozone gas, and a known apparatus may be adopted. For example, MEO-1.0AH manufactured by Meidensha is exemplified.

  By storing the ozone chamber 4 in a heat-insulated vacuum vessel 6 in a vacuum state, waste of heat energy around the ozone chamber 4 is suppressed. The heat insulating vacuum vessel 6 is provided so that ozone can be taken out from the ozone chamber 4. A cooling metal block 7 is installed at the bottom of the adiabatic vacuum vessel 6. An ozone chamber 4 is mounted on the cooling metal block 7. The cooling metal block 7 supplies heat introduced from the variable thermal resistance control device 5 to the ozone chamber 4. Thus, the ozone chamber 4 is cooled by the refrigerator 2 through the heat conductor 3, the variable thermal resistance control device 5, and the cooling metal block 7.

  The individual temperature control of each ozone chamber 4 for continuously generating ozone gas is performed by operating a variable thermal resistance control device 5 of each ozone chamber 4 or a heater provided in the cooling metal block 7 as in the prior art.

As the variable thermal resistance control device 5, for example, as shown in FIGS. 2A and 2B, a variable thermal resistance block 50 formed in a casing shape to which a thermal resistance variable medium is supplied and discharged. There is. The variable thermal resistance block 50 supplies, discharges, or changes the thermal resistance variable medium, or mixes different types of thermal resistance variable media, and supplies the variable resistance thermal resistance medium. The thermal resistance between 51 and the bottom plate part 52 is adjusted. Thereby, the heat conduction from the refrigerator 2 to the ozone chamber 4 is adjusted, and the temperature of the cooling metal block 7 can be controlled. The thermal resistance variable medium is preferably not liquefied at the temperature on the cold head 11 side. For example, helium, hydrogen, nitrogen, oxygen, argon, neon, or any of the above except for a combination of hydrogen and oxygen is combined. Examples thereof include mixed gas.

  In addition, by providing a plurality of variable thermal resistance control devices 5 as shown in FIG. 1, the variable thermal resistance block 50 is individually supplied, discharged or changed, or mixed with different media. Thus, by adjusting the thermal resistance between the top plate portion 51 and the bottom plate portion 52 and individually controlling the temperature of the cooling metal block 7 in the heat insulating vacuum vessel 6, the liquefaction of ozone in the ozone chamber 4, the liquid Ozone gas can be continuously supplied by sequentially evaporating ozone and discarding residual ozone.

  Furthermore, the variable thermal resistance control device 5 controls the gas pressure in the variable thermal resistance block 50 so that the thermal resistance increases when the temperature in the ozone chamber 4 is increased when ozone is supplied outside or disposed of. To do. On the other hand, when the temperature in the ozone chamber 4 is lowered in order to cool or liquefy ozone, the internal pressure of the variable thermal resistance block 50 is controlled so that the thermal resistance becomes small. In this way, the variable thermal resistance block 50 can arbitrarily control the thermal resistance by controlling the internal pressure, so that the heater heating amount necessary for temperature control can be reduced. Moreover, since the variable resistance block 50 can control the temperature in the ozone chamber 4 to a predetermined value in accordance with each step, heat from the high-temperature vessel (the heat-insulated vacuum container 6 including the ozone chamber 4) to the low-temperature vessel. Is reduced, and stable multi-bessel operation is possible.

The ozone chamber 4 is arranged in series on the heat conductor 3, and the distance from the cold head 11 to each ozone chamber 4 on the heat conductor 3 is different, but the heat depends on the cooling performance of the refrigerator 2. Since the conductor 3 can be cooled to a uniform temperature, it has been confirmed that the same temperature control is possible for each ozone chamber 4. When it becomes necessary to dispose more ozone chambers 4 or the like, it can be dealt with by correcting the temperature by operating the variable thermal resistance control device 5 or a heater (not shown).

  Like the ozone generator 1 of this embodiment, the linear heat conductor 3 is used to arrange the refrigerator 2 and the ozone chamber 4 in a single line, so that a compact configuration can be obtained. This contributes to the reduction of the width or thickness of the housing when housed in a container.

In addition, the structure of the ozone generation unit, in particular, it is not necessary to make a special configuration between the cold head 11 and the cooling metal block 7, and it has a simple configuration without a mechanical moving part, further reducing the size and cost of the apparatus. Down can be possible.

Furthermore, the refrigerator 2 is thermally connected in the vicinity of the short side of the lower surface 32 of the heat conductor 3, so that a space is secured below the ozone chamber 4. Thereby, the space can be used effectively. In addition, since the refrigerator 2, the cold head 11, and the like are not disposed directly below the ozone chamber 4 , fatal damage to peripheral devices such as the refrigerator 2 is avoided even in the event of an explosion.

(Embodiment 2)
In the first embodiment, the thermal conductor 3 and the variable thermal resistance control device 5 are directly connected, but the variable thermal resistance control device 5 may be supported by a support member.

  As the support member, for example, a support member 8 shown in FIGS. 2A and 2B, a stage unit 81 to which the variable thermal resistance control device 5 is fixed, and the stage unit 81 are supported. Some of them have a support portion 82 connected to the end face on the long side of the heat conductor 3. The stage part 81 and the support part 82 are formed by bending a plate-like member made of a metal material. The variable thermal resistance control device 5 is fixed to the stage portion 81 with a bolt 83. The support portion 82 is fixed to the end surface on the long side of the heat conductor 3 by a bolt 84. The metal material constituting the support member 8 may be the same as the material constituting the heat conductor 3 in consideration of the heat conduction efficiency.

  As described above, according to the ozone generator 1 of the present embodiment, the variable thermal resistance control device 5 is supported by the metal support member 8, so that the thermal conductor 3 and the variable thermal resistance control device 5 Increases the heat transfer efficiency. In addition, even if the ozone in the ozone chamber 4 explodes and the ozone chamber 4 vibrates, the shock of the vibration is mitigated by the buffering action of the support member 8, and damage to surrounding equipment and members can be suppressed. .

(Embodiment 3)
The heat conductor 3, the variable thermal resistance control device 5, and the cold head 11 are stored in the storage unit 9 as in the ozone generation device 10 shown in FIGS. 3 (a) to 3 (c). The storage unit 9 may be connected to the vacuum heat insulating container 6. If the plurality of vacuum heat insulating containers 6 in which the ozone chambers 4 are stored in this way are united with the storage unit 9, each of the components can be provided by providing a plurality of the units when increasing the amount of ozone gas generated. This can be easily handled without considering the increase in size (capacity) of the members. Moreover, since the heat conductor 3, the variable thermal resistance control device 5, and the cold head 11 are isolated from the outside air by the storage unit 9, waste of heat energy is suppressed.

The storage unit 9 shown in FIG. 3A stores the variable thermal resistance control device 5, the heat conductor 3, and the cold head 11 according to the first embodiment. The storage unit 9 includes a container 91 for storing the heat conductor 3 and the variable thermal resistance control device 5 provided thereon, and a container 92 for storing the cold head 11 and the vicinity of one end of the heat conductor 3. The vacuum heat insulating container 6 storing the ozone chamber 4 is in a state of being thermally connected to the container 91. Since the containers 91 and 92 are only required to store the variable thermal resistance control device 5, the heat conductor 3, and the cold head 11 , the shapes thereof are not particularly limited.

3 (b) and FIG. 3 (b) store the variable thermal resistance control device 5, the support member 8, the heat conductor 3, and the cold head 11 (not shown) according to the second embodiment. The illustrated container 91 is formed in a cylindrical container. The vacuum heat insulating container 6 storing the ozone chamber 4 is in a state of being thermally connected to the container 91. In addition, since the variable thermal resistance control device 5, the heat conductor 3, and the cold head 11 need only be stored, the shape of the container 91 is not limited to the illustrated form.

The schematic block diagram which showed the ozone production | generation apparatus which concerns on one Embodiment of this invention. (A) The side view which showed the connection form of a variable thermal resistance control apparatus and a heat conductor. (B) Sectional drawing which showed the connection form of a variable thermal resistance control apparatus and a heat conductor. (A) The schematic block diagram which showed the ozone production | generation apparatus which concerns on one Embodiment of this invention. (B) The side view which showed one Embodiment of the container which stored the variable thermal resistance control apparatus and the heat conductor. (C) Sectional drawing which showed one Embodiment of the container which stored the variable thermal resistance control apparatus and the heat conductor. The schematic block diagram which showed the conventional ozone production | generation apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,10 ... Ozone generator 2 ... Refrigerator 3 ... Thermal conductor 31 ... Upper surface, 32 ... Lower surface 4 ... Ozone chamber 5 ... Variable thermal resistance control device 50 ... Variable thermal resistance block, 51 ... Top plate part, 52 ... Bottom plate Part 6 ... Vacuum insulation container 7 ... Cooling metal block 8 ... Support member 81 ... Stage part, 82 ... Support part, 83, 84 ... Bolt 9 ... Storage part 91, 92 ... Container

Claims (3)

A heat conductor thermally connected to the refrigerator;
A plurality of ozone chambers having a variable thermal resistance control device thermally connected to the heat conductor;
The heat conductor is made of a metal material and is formed into a plate shape whose main surface is rectangular,
The heat in the upper side of the conductor are arranged in series the plurality of variable thermal resistance controlling device along the long sides of the main surface of the thermal conductor,
The variable thermal resistance control device is individually supported by the heat conductor by a metal support member,
The support member includes a plate-like stage portion to which the variable thermal resistance control device is fixed, and a plate-like support portion that supports the stage portion and is connected to an end face on the long side of the heat conductor. It made it <br/> ozone generating apparatus according to claim. The ozone generator according to claim 1, wherein the refrigerator is thermally connected in the vicinity of the short side of the lower surface of the heat conductor. Ozone generating apparatus according to claim 1 or 2, further comprising a storage unit for storing said variable thermal resistance control unit and the heat conductor.

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