KR20140108293A - Method of feeding hydrogen fluoride into an electrolytic cell - Google Patents

Abstract

The present invention relates to a method for supplying hydrogen fluoride as a feed material to an electrolytic cell (electrolytic cell) for producing a fluorine element (by electrolysis) from a molten salt electrolyte, comprising the steps of: (a) feeding hydrogen fluoride (HF) (C) to an electrolytic cell from a hydrogen fluoride feed unit, (b) through a hydrogen fluoride feed line, wherein the required amount of hydrogen fluoride feed to a limited fluoride feed capacity is less than the required amount of hydrogen fluoride feed When compared to the maximum (maximum) HF feed capacity of the feed line of 80 kg / h and the associated short full HF feeding interval as in conventional methods, Is supplied to the electrolytic cell as the gas HF, preferably at a substantially less HF feed rate per hour (kg / h) over the interval. In another aspect, the present invention also relates to an electrolytic cell for the production of a fluorine element by electrolysis of a molten HF adduct of KF, wherein the HF feed line comprises, in accordance with the method of feeding hydrogen fluoride as a feed material according to the present invention Loses.

Description

METHOD OF FEEDING HYDROGEN FLUORIDE INTO AN ELECTROLYTIC CELL [0002]

The present invention claims priority benefit from EP Patent Application No. 11195430.1, filed December 22, 2011, the entire contents of which are incorporated herein by reference for all purposes.

The present invention relates to an improved method of supplying hydrogen fluoride as a feed material to an electrolytic cell (electrolytic cell) for production by electrolysis of a fluorine element. Such a fluorine element is intended as a supply (carrier) in a method of manufacturing an electronic device.

Hydrogen fluoride is particularly useful as a feed material in chemical manufacturing processes, for example, in a manufacturing process by electrolysis of molecular fluorine (F ₂ ), and is useful, for example, as a chamber cleaning gas in the semiconductor industry and other fluorinated chemicals It is also useful as a feed material in materials, e.g., fluorinated hydrocarbon manufacturing processes.

The fluorine element (F ₂ ) not only has zero global warming potential (GWP) but also has no effect on the ozone layer. Fluorine elements are useful, for example, as fluorinating agents in the preparation of fluorinated polymers, especially as chamber cleaners in the preparation of fluorinated solvents for Li-ion batteries, and in electronic devices, particularly semiconductors, photovoltaics, &Quot;" MEMS ") and TFT (thin film transistor for flat panel display or liquid crystal display) and the like.

With respect to use as electronic devices, especially as caustics for semiconductor, photovoltaic, MEMS and TFT fabrication, there are a number of successive steps involved in depositing layers of this device and etching portions of these layers. Fluorine can be used to etch layers of very different structures, for example, to etch silicon containing layers or other layers of volatile reaction products, such as tungsten forming compounds. The etching may be performed in a high temperature method or a plasma assisted manner.

(Typically a chamber in which the constituent layers are deposited on a substrate via chemical vapor deposition, such as plasma enhanced CVD, metal organic CVD or low pressure CVD)) during chamber cleaning , Unwanted buildup is formed in the chamber walls and internal structural components, and this buildup must be removed regularly. This is accomplished by plasma enhanced processing or heat treatment of the deposit using a fluorine element that is a chamber cleaner.

Particularly, when the fluorine element is used not only as a corrosive agent but also as a chamber cleaner, the fluorine element is preferably very pure. The incorporation of water, carbon dioxide, nitrogen and oxygen is considered undesirable.

The fluorine element can be produced by various methods, but as already mentioned above, it is often produced by electrolysis from hydrogen fluoride (HF), which is the feed material in electrolysis and the source of the fluorine element. When an electrolyte salt is present, HF releases fluorine if a voltage greater than 2.9 V is applied. Indeed, the voltage is often maintained in the range of 8 volts to 11 volts.

The molten HF adduct of KF (often represented by the formula KF (1.8-2.3) HF) is a preferred electrolyte salt. HF is fed to the reactor containing the molten electrolyte salt and F ₂ is formed by electrolysis from HF according to equation (1) by applying a voltage and passing current through the molten salt:

2HF - > H ₂ + F ₂ (One)

After fluorine is produced by an electrolytic manufacturing process (or any other method), the fluorine can be stored in a pressurized cylinder and carried to the site to be used. For plants with more F ₂ demand, F ₂ is preferably produced directly on site or "over the fence".

WO 2004/009873 discloses a method for producing fluorine by electrolysis of hydrogen fluoride and an apparatus therefor. Fluorine is produced by electrolysis from HF in a fluorine generating cassette. Fluorine can be used in the manufacture of electronic devices, for example in the manufacture of TFTs.

The apparatus comprises a plurality of individual fluorogenic cassettes; The individual fluorine generating cassettes being operably connected to a fluorine gas distribution system for remote use and consumption of the fluorine gas; The fluorogenic cassette may be separate from the gas distribution system separately and may be removed from the remote holding device. According to the reference WO 2004/009873, the supply of liquid hydrogen fluoride takes place in the tank. The hydrogen fluoride vaporizer vaporizes liquid hydrogen fluoride from the tank and feeds the vaporized gas to the cassette to keep the concentration of the electrolyte (composed of the melt HF adduct of KF mentioned above) constant.

During electrolysis and formation of fluorine elements, a corresponding amount of hydrogen fluoride (HF) is consumed. As a result, for subsequent formation of fluorine, new HF is sometimes supplied to the electrolytic cell to maintain the level of HF available as a source of fluorine to a certain extent such that electrolysis can be performed to produce fluorine at acceptable purity . Usually, for example, in view of the preferred electrolyte salt of a molten HF adduct of KF, the range of HF generally varies depending on the formula KF (1.8-2.3) HF. At the state of the art, it is quite common to operate the electrolytic cell by supplying a large amount of HF in a large amount over a short interval, for example, by supplying HF at a supply amount of about 80 kg / h HF or less or a much higher supply amount per interval.

However, supplying a large amount of HF over short intervals may cause problems in uniformly maintaining the composition and temperature of the electrolyte depending on space and time, and consequently, impurities such as CF ₄ , OF ₂ , It has been observed by the present inventors that the formation of O ₂ is substantially increased and fluorine may be produced inferior in terms of purity. Feeding HF in large quantities over short intervals can result in higher HF concentrations that can lead to excessive HF feed conditions resulting in the formation of impurities such as OF ₂ , O ₂ , CF ₄ , CO ₂ or SO ₂ F ₂ It causes. In addition, an increase in the amount of current can lead to the formation of CF ₄ , CO ₂ or SO ₂ F ₂ . Thereafter, a decrease in the HF level causes technical problems associated with the carbon anode, and thus additional formation of an undesirable impurity, CF ₄ , takes place.

In many fields, fluorine with high purity or at least impurities is present in the minimum in the on-site process, which must be as simple as possible, have little interference with human force, and continuously produce high purity fluorine which requires at least the additional purification means Fluoride is needed.

It is therefore an object of the present invention to provide an improved method of supplying HF to an electrolytic cell in order to produce fluorine, in particular fluorine having a minimum impurity, most preferably high purity fluorine. In particular, it is an object of the present invention to provide an improved method and apparatus which can maintain the temperature more uniformly and which allows the composition of the electrolyte to be more homogeneous and / or depending on space and time, thereby minimizing or preventing the formation of undesirable impurities in the fluorine Method.

The object of the present invention is achieved by a modified HF supply to the electrolytic cell to produce fluorine when compared to the standard method of modern HF supply. According to the present invention, the HF consumed in the electrolysis is compensated for by adding the required amount of fresh HF for a longer interval in a more relaxed manner. The term " mitigated " means that, for example, physico-chemical process parameters or electrolytes are less likely to be interfered with in a potentially bad direction, and electrolytic conditions are more stably conserved during HF feeding (e.g., And the composition remains more uniform in space and time) and at the same time does not adversely affect fluorine production efficiency. The term " relaxed " also results in that impurity formation can be minimized or even impurity formation can be prevented.

Accordingly, the present invention provides a process for producing a fluorine element from a molten salt electrolyte, comprising the step of supplying new hydrogen fluoride as a feed material to the electrolytic cell (electrolytic cell) to supplement the consumed HF, There is provided a method of producing F ₂ in an electrolytic cell (electrolytic cell) to produce a fluorine element (by electrolysis) from a molten salt electrolyte by electrolysis, wherein F ₂ and H ₂ are formed, (A) from a hydrogen fluoride feed unit, (b) through a hydrogen fluoride feed line, (c) to an electrolytic cell, wherein the fresh HF The supply is limited to an HF flow rate of less than 10 kg / h of HF per tonne of electrolyte.

Briefly stated, the present invention provides a method for producing F ₂ by electrolysis of HF contained in an electrolyte, wherein F ₂ and H ₂ are formed, the spent HF is supplemented with the supply of fresh HF, Is limited to an HF flow rate of less than 10 kg / h of HF per tonne of electrolyte. Preferably, the HF flow rate is limited to 5 kg / h or less of HF per tonne of electrolyte. The term " HF flow rate " is used interchangeably with the term " HF feed rate per hour ". The term " tone " in the context of the present invention refers to a metric according to the metric system. The term " electrolytic cell " may be used interchangeably with the term " electrolytic cell ". The fluorine element is produced by electrolysis.

It should be noted that the apparatus for the generally used F ₂ electrolysis preparation (essentially equimolar H ₂ production as a by-product) has an HF consumption of about 1 kg / h to 3 kg / h per ton of electrolyte. Therefore, in order to replenish the spent HF, a new HF should be supplied from 2 kg to 6 kg per hour to an apparatus having a capacity of 2 tons of electrolyte. Often, the amount of HF consumed in such an apparatus having an electrolyte capacity of about 2 tons is 3 kg / h to 6 kg / h.

Therefore, in general, the present invention is able to more easily maintain the internal temperature of the cell, even though HF is added to the electrolytic cell, to a desired range that has been set, and the electrolytic composition varies depending on space and time, Or more uniformly throughout the electrolytic cell including the inflow region. A further advantage is that the formation of impurities can be minimized or prevented, producing only fluorine which needs to be subjected to only a limited additional purification means, or fluorine having a purity ready for use in the process in which it is to be used .

For example, in the expression " one step ", the word " one " is not intended to limit expression in a single step. The term " comprising " includes the meaning of " consisting of. &Quot;

Often, the HF feed line is constructed so that the HF is supplied at a much higher flow rate to supplement the HF. For example, the feed line is constructed such that the HF can be introduced into the electrolyzer at less than 80 kg / h. According to the present invention, the maximum HF flow rate is significantly less. Accordingly, the present invention is particularly directed to a method of supplying hydrogen fluoride as a feed to an electrolytic cell (electrolytic cell) to produce a fluorine element (by electrolysis) from a molten salt electrolyte, (a) from a hydrogen fluoride feed unit, (b) through a hydrogen fluoride feed line, and (c) to an electrolytic cell, wherein the required amount of hydrogen fluoride feed to a defined fluorine production capacity is When compared with the maximum (maximum) HF feed capacity of the feed line of 80 kg / h and the associated short full HF feeding interval as is the case, Is supplied to the electrolytic cell as HF supply amount (kg / h) per hour, preferably as gas HF.

Hydrogen fluoride (HF) may be added to the electrolytic cell either as a liquid HF feed or as a gaseous HF feed. &Quot; Hydrogen fluoride (HF) " is understood to represent, in particular, anhydrous hydrogen fluoride. When hydrogen fluoride is contained in the storage container, the hydrogen fluoride is generally liquid. Thus, in the case of a liquid HF feed, this HF is drawn directly from the storage vessel as large as a desired amount, for example by pumping, or simply by applying pressure to the storage vessel and pushing the HF into the feed line, ) To the electrolytic cell (c). In the case of a gaseous HF feed, the storage vessel is additionally equipped with an evaporator, whereafter the liquid HF is evaporated from the storage vessel (a) and conveyed to the electrolytic cell (c) via the feed line (b). When a liquid HF feed is selected, measures must be taken to avoid clogging (plugging) of the feed line by accidental freezing of the molten electrolyte salt in the HF outlet area in the electrolyte inside the cell. As part of the guidance, plugging can be observed, for example, in a fluid orifice with an inner diameter of about 0.3 mm. Also, in the case of liquid HF feedstocks, measures must be taken to avoid potential disturbance of the electrolyte surface. For example, when a fluid orifice having an inner diameter of about 0.4 mm is used as part of the guide, severe agitation may be observed on the electrolyte surface. Thus, in this embodiment of the invention, the method may optionally be operated with further adjustment of other process parameters, as well as using a fluid orifice with an inner diameter of about 0.35 mm.

In a preferred embodiment of the present invention, a gaseous HF feed is selected to supply HF to the electrolytic cell. In this preferred embodiment, consequently, the present invention relates to a method of feeding hydrogen fluoride as a feed material to an electrolytic cell (electrolytic cell) to produce a fluorine element (by electrolysis) from a molten salt electrolyte, Comprising the steps of: (a) transferring hydrogen fluoride (HF) from a hydrogen fluoride feed unit to (b) a hydrogen fluoride feed line and (c) to an electrolytic cell, wherein the required amount of hydrogen fluoride feed to a limited fluorine production capacity is Is supplied to the electrolytic cell as gas HF at a substantially lower HF feed rate (kg / h) over a long feed interval when compared to the maximum HF feed rate, It is equal to or less than 25% of the supply. Preferably, the present invention relates to a method of feeding hydrogen fluoride as feed material to an electrolytic cell, wherein the maximum (maximum) feed rate of the feed line is 80 kg / h and the associated short, uninterrupted HF feed interval, And includes a short, non-continuous HF feed interval as applied in conventional, conventional methods.

In accordance with the present invention, an improved method of supplying HF is concerned with producing fluorine elements. The fluorine element in the content of the present invention is produced by electrolysis using hydrogen fluoride (HF) as a supply source for electrolysis and a fluorine element. In the presence of an electrolyte salt, HF releases fluorine if a voltage of 2.9 V or higher is applied. Virtually the voltage is often maintained in the range of 8 volts to 10 volts or 11 volts.

HF is advantageously supplied such that the levels of electrolyte salts and HF in each cell do not exceed certain upper and lower limit levels. Preferably, the electrolytic cell further comprises a sensor for measuring the internal temperature of the cell, the internal level of the cell or cells, the pressure and pressure difference, the anode current and voltage, and the gas temperature. The cell is cooled with cooling water having a temperature of about 80 ° C to 95 ° C.

Usually, among the contents of the present invention, the molten HF adduct of KF preferably having the formula KF (1.8-2.3) HF is the preferred electrolyte salt. HF is supplied to the reactor containing the molten electrolyte salt, and F ₂ is formed from HF by electrolysis according to the above equation (1) by applying a voltage and passing current through the molten salt.

Thus, in one embodiment, the present invention is directed to a method of supplying hydrogen fluoride, wherein the molten salt electrolyte has a HF range that is based on the molten HF adduct of KF, preferably the formula KF (1.8-2.3) HF The branch is a molten HF adduct of KF.

Typically, in one embodiment, the present invention relates to a method of supplying hydrogen fluoride, wherein the hydrogen fluoride feed requirements associated with the fluorine production capacity of the electrolytic cell are such that the HF feed range is from the point of view of a device having an electrolyte capacity of 2 tonnes H to a range of 2 kg / h to 5 kg / h, preferably from 3 kg / h to 4 kg / h of HF.

Typically, in another embodiment, the present invention relates to a method of supplying hydrogen fluoride, wherein the amount of HF feed per hour (kg / h) for a device having a 2 ton electrolyte capacity is less than 20 kg / h, preferably less than 15 kg / h, and more preferably less than 10 kg / h. In a variation of this embodiment of the invention, the amount of HF feed per hour (kg / h) ranges from 1 kg / h to 20 kg / h, preferably from 1 kg / h to 15 kg / h, Preferably in the range of 1 kg / h to 10 kg / h. More specifically, the HF feed rate per hour (kg / h) is in the range of 2 kg / h to 10 kg / h, preferably in the range of 4 kg / h to 10 kg / h, more preferably 6 kg / Kg / h, even more preferably from 7 kg / h to 9 kg / h, and the HF feed rate per hour is most preferably about 8 kg / h per 2 tonnes of electrolyte. The term "about" in the present context means that the HF feed rate per hour may vary slightly to around 8 kg / h, which means, for example, slightly less than or slightly greater than 8 kg / h. Therefore, the value may vary by about +/- 0.5 kg / h, so the HF feed rate is preferably 8 +/- 0.5 kg / h.

According to the method of the present invention for supplying hydrogen fluoride to the electrolytic cell to produce fluorine elements from the molten salt electrolyte by electrolysis, the HF feed rate per hour (kg / h) described above can be reached by several means . For example, in one embodiment of the present invention, the amount of HF feed per hour (kg / h) can be reached by adjusting the HF flow rate by means of a pressurizing or pumping means. Alternatively, the HF feed line may have an orifice that reduces the HF flow rate. The preferred diameter of the orifice ranges from 1 mm to 1 cm. The diameter will be correlated with the amount of HF consumed per unit of time.

A plant supplied with HF in an amount of less than 20 kg / h, often in the range of 7 kg / h to 9 kg / h, is associated with the preferred embodiment. Thus, in a preferred embodiment of the present invention, the tube (liquid level sensing tube) contained in the electrolytic bath (electrolyte) is characterized in that the (internal) diameter of the fluid orifice in the tube is about 2.5 mm. The term " about " in this context means that the value 2.5 mm may be slightly different, for example, the maximum value ± 0.1 mm to 0.25 mm, preferably the maximum value ± 0.1 mm to ± 0.2 mm. Thus, the fluid orifice diameter may be characterized by 2.5 +/- 0.25 mm, 2.5 +/- 0.2 mm, or 2.5 +/- 0.1 mm, and so on. It should be noted that the orifice can vary depending on the amount of HF to be supplied per hour and the inlet pressure of HF. To ensure that the HF feed rate per hour is greater than 20 kg / h, larger diameter orifices may be useful. A smaller diameter orifice may be advantageous to ensure that the feed rate of HF is much less than, for example, 6 kg / h. For an orifice with a diameter of 2.5 mm, the cross-sectional area is about 5 mm 2. The cross-sectional area will correlate with the amount of HF passing through the orifice per hour. It is assumed that the relationship between the supply amount and the cross sectional area of HF per hour is linear. If the amount of HF per hour is doubled, it is assumed that an orifice with twice the cross-sectional area should be used. It is assumed that an orifice having a diameter in the range of 1 mm to 1 cm may be applied to the feed line. Nonetheless, smaller or larger diameter orifices could also be used if desired.

In another preferred embodiment of the method of the present invention for supplying hydrogen fluoride to an electrolytic cell to produce a fluorine element from a molten salt electrolyte by electrolysis, HF is supplied to the electrolytic cell as a gas, and the supply amount of HF (kg / h can be reached by adjusting the fluid orifice diameter in the hydrogen fluoride feed line (b) (preferably by using a fluid orifice whose internal diameter in the hydrogen fluoride feed line (b) is about 2.5 mm). The term " fluid orifice " refers to a region from its HF reservoir to the location of the fluid orifice, and the inner diameter of the submergence zone in the electrolyte following this location is greater than the inner diameter of the fluid orifice of 2.5 mm (Generally large) hydrogen fluoride feed line. For the purposes of the present invention, if the inner diameter of the HF feed line having an inner diameter of the front portion and a rear portion of the fluid orifice of greater than 2.5 mm is reduced to 2.5 mm at the location of the end portion of the HF feed line in the electrolyte It would be very satisfying if it did. This reduction in the inner diameter of the HF feed line may, in its most general sense, be accomplished by any suitable construction means that reduces the inner diameter of a single point in the pipe to make the orifice diameter as necessary.

In another preferred embodiment of the method of the present invention for supplying hydrogen fluoride to an electrolytic cell to produce a fluorine element from a molten salt electrolyte by electrolysis, the method of supplying hydrogen fluoride is characterized in that the HF supply (kg) and the supply interval (h) is controlled by the automatic valve. Normally, such an automatic valve operates under preset conditions, and the total condition in the electrolytic cell when electrolysis progresses over time, for example, the temperature, the HF content, the electrolyte level, the electric current upon electrolysis of the molten salt electrolyte Or any other relevant parameter, or the quality of the fluorine produced, optionally operating the HF feed parameters from time to time during the fluorine production process, as appropriate.

In a preferred embodiment, the maximum flow rate of HF per hour that can be reached is greater than the total consumption of HF per hour. For example, the HF flow rate is 6 kg / h to 10 kg / h, and the consumption amount of HF is 2 kg / h to 6 kg / h. In this case, the HF feed rate per hour may be greater than the actual consumption, so the HF feed may be stopped for any period of time. It is advantageous to introduce an inert gas into the HF supply line for a period during which HF is not supplied. In a preferred embodiment, the electrolyte level is measured during a period when HF is not supplied. The electrolyte level can be measured, for example, in the manner described in the following paragraphs.

The HF feed line is submerged in the molten electrolyte. Generally, the level of electrolyte in the flooded portion of the feed line and the level of electrolyte around the flooded line are essentially the same. When the HF feed is stopped, the inert gas is pushed into the submerged feed line, and the pressure of the inert gas prevents the molten electrolyte from entering, so that the electrolyte is essentially nonexistent in the submerged line. In order to prevent the electrolyte from entering the flooded line, the pressure of the inert gas must be higher or lower depending on the level of the molten electrolyte. The pressure required to prevent entry of the electrolyte can be calibrated based on the level of the electrolyte in the cell. Depending on the measured pressure, the HF feed can be adjusted: if the electrolyte level is relatively low, the HF flow rate can be adjusted to a larger value and / or the feed time can be extended; If the level is relatively high, the HF flow rate can be adjusted to a smaller value and / or the feed time can be shortened.

In a preferred embodiment, the ratio of HF flow rate (kg per hour) to HF consumption (kg per hour) is between 1.2: 1 and 4: 1. Preferably between 1.5: 1 and 3: 1. Thus, it is possible to determine the intervals at which HF is supplied and the intervals at which HF is not supplied, but the electrolyte level is measured by introducing an inert gas into the supply line as mentioned above. It is desirable to measure the electrolyte level by increasing the number of HF feeds. For example, it can be expected that HF is supplied at 30 times per hour or less, and accordingly, the electrolyte level is measured at 30 times per hour or less. In this case, the HF feed will last for 33 seconds to provide an example with a time ratio of 1.2: 1, depending on the ratio of HF flow and consumption, the next level measurement will last for 27 seconds, then the HF feed for 33 seconds And the next level measurement will continue for 27 seconds, or the like. If the ratio is 2: 1, the 30-second HF feed will be stopped for 30 seconds to measure the electrolyte level. Of course, the expert can pre-determine the liquid level measurement and the duration of the HF supply according to his or her will. As the number of HF feeds and the period during which HF is not transported increases, F ₂ production operations will be more smooth.

The duration of the HF feed which lasts for preferably from, for example, 1 minute to 60 minutes, 1 minute to 50 minutes, 1 minute to 40 minutes, 1 minute to 30 minutes, 1 minute to 20 minutes, or 1 minute to 10 minutes, Useful spacing; Preferably shorter intervals can be selected, for example from 1 minute to 5 minutes, preferably from 1 minute to 4 minutes, more preferably from 1 minute to 3 minutes, even more preferably from 1 minute to 2 minutes , And most preferably about one minute, can be highly recommended. If the period is expressed in seconds, it is much shorter intervals, for example 1 second to 60 seconds, 1 second to 50 seconds, preferably 20 seconds to 50 seconds, 1 second to 40 seconds, preferably 20 seconds 40 seconds, 1 second to 30 seconds, preferably about 30 seconds, 1 second to 20 seconds, or 1 second to 10 seconds is a period that can be substantially useful and recommended; Though much shorter intervals may be chosen, for example between 1 second and 5 seconds, between 1 second and 4 seconds, between 1 second and 3 seconds, between 1 second and 2 seconds, and between about 1 second, desirable. The periods during which the HF is not carried during plant operation correspond to the remaining hours.

Of course, no pressure needs to be measured at each interval when no HF is supplied.

Pressure measurements can be performed in the F ₂ and H ₂ sections of the cell. If the pressure measurement is carried out in the F ₂ zone of the cell (this case is preferred), N ₂ or F ₂ is the preferred inert gas. If the pressure measurement is carried out in the H ₂ zone (which is also desirable in this case), N ₂ or H ₂ is the preferred inert gas.

In a preferred embodiment, N ₂ or any other inert gas, such as a Group 0 gas, may pass through the HF line or HF line to prevent the molten electrolyte from flowing into the HF line or HF lines .

It is also possible to use an automated system to regulate the amount of HF to be fed, the duration of the HF feed and the level of the liquid, depending on the data provided by the liquid level measurement method.

In the present invention relating to a method for supplying hydrogen fluoride to an electrolytic cell, HF may be supplied from any type of hydrogen fluoride storage vessel. The hydrogen fluoride storage vessel may be a single hydrogen fluoride storage vessel of varying sizes or may be a hydrogen fluoride storage unit containing a plurality of stationary or optionally removable hydrogen fluoride storage vessels which may be connected to the electrolytic bath through a hydrogen fluoride feed line .

The present invention relates in particular to a process for the production of hydrogen fluoride, comprising: (i) filling the at least one mobile hydrogen fluoride storage vessel with hydrogen fluoride, (ii) transporting the hydrogen fluoride storage vessel to a hydrogen fluoride supply unit, (iii) And (iv) supplying hydrogen fluoride from the hydrogen fluoride storage vessel to the hydrogen fluoride feed line. The present invention relates to a process for producing hydrogen fluoride, In addition, it is preferable that the evaporation apparatus for evaporating the liquid HF is provided with a hydrogen fluoride storage vessel, or such an evaporation apparatus for evaporating the liquid HF as described above may be provided in a part of the plant where HF is to be provided And may be connected to a hydrogen fluoride storage vessel or storage unit and a hydrogen fluoride feed line. Other additional means, for example safety devices such as HF sensors, HF destruction systems, may also be present at the locations of the hydrogen fluoride storage vessels or storage units.

In a preferred embodiment, the HF storage vessel used in the invention comprises an automatic HF level sensor. In particular, the HF storage vessel can be installed on the weighing scale. In this preferred embodiment, preferably the process control system, in particular the automatic process control system, is configured to shut off the remote control valve of the first HF vessel (with the interior being empty) and another second hydrogen fluoride storage vessel To open the remote control valve. This embodiment is particularly effective in preventing the HF valve from being manually operated, and is also effective in ensuring continuous supply of HF.

In a preferred embodiment, the valve may be actuated to be automatically shut off when the process is interrupted, for example, in process equipment connected to the HF supply line when in an abnormal operating state.

In another preferred embodiment, the valve may be operated to automatically shut off when HF leaks in the hydrogen fluoride feed unit according to the present invention. Such HF leakage can be caused, for example, by leakage of an optional flange connection inside the HF storage vessel. The valve avoids the need to access the hydrogen fluoride feed unit, especially in this case.

More preferably, the storage vessels can be isolated from the HF feed line by a double shut-off valve having a closed shut-off space. In such a case, the hydrogen fluoride supply unit according to the present invention additionally includes one or more interspace vent valves connected to one or more closed shut-off spaces as appropriate. The interspace vent valve is typically operable to remove selectively hydrogen fluoride from the enclosed containment space. Removal can be performed, for example, by applying a vacuum. In another embodiment, the removal may be performed, for example, by flushing an inert gas and / or a pressurized purging gas, for example dry air, preferably nitrogen, into the enclosed shut-off space. In one embodiment, removal can be performed continuously. Preferably, removal is performed discontinuously, especially when connected to / connected to a supply line or away from this line. If appropriate, the gas recovered from the closed containment space is vented appropriately to an HF destruction unit, for example a scrubber.

In one embodiment of the present invention, a method of supplying hydrogen fluoride to produce fluorine by electrolysis is characterized in that the fluorine element produced in cell (c) is used in an electronic device manufacturing method, Is intended to be used as a corrosive liquid or chamber cleaner in the process.

In a preferred embodiment of the present invention, a method of supplying hydrogen fluoride to produce fluorine by electrolysis is characterized in that the electronic device is selected from the group consisting of a semiconductor, a photovoltaic cell, a MEMS, and a TFT. In one embodiment of the invention, fluorine is used as a chamber cleaner and corrosive agent for fabrication of electronic devices, particularly semiconductors, photovoltaic cells, microelectromechanical systems (" MEMS ") and TFTs (flat panel displays or thin film transistors for liquid crystal displays) do. In the use of fluorine as an etchant for electronic devices, particularly semiconductors, photovoltaic cells, MEMS, and TFTs, several sequential steps are needed to laminate multiple layers and to etch some of these layers. Fluorine can be used to etch layers of very different structures, for example, to etch silicon containing layers or other layers of volatile reaction products, such as tungsten forming compounds. The etching may be performed in a high temperature method or a plasma assisted manner. (Typically a chamber in which the constituent layers are deposited on a substrate via chemical vapor deposition, such as plasma enhanced CVD, metal organic CVD or low pressure CVD)) during chamber cleaning , Unwanted buildup is formed in the chamber walls and internal structural components, and this buildup must be removed regularly. This is accomplished by plasma enhanced processing or heat treatment of the deposit using a fluorine element that is a chamber cleaner.

Particularly, when the fluorine element is used not only as a corrosive agent but also as a chamber cleaner, the fluorine element is preferably very pure. The incorporation of water, carbon dioxide, nitrogen and oxygen is considered undesirable. The fluorine element produced in accordance with the present invention meets this quality requirement as already explained in more detail above.

In another preferred embodiment of the present invention, a method of supplying hydrogen fluoride for the production of fluorine by electrolysis comprises the steps of " in situ " or " off-site "Quot; is generated.

If desired, fluorine can be produced in situ. This is a preferred embodiment of the present invention. As described in WO 2004/009873, fluorine can be produced in one or more satellite plants, for example, a fluorogenic cassette. If desired, each cassette can be disposed in one or more process chambers in which etching is performed; Or a plurality of fluorine generating cassettes are connected to a fluorine gas distribution system connected to the chambers. The low temperature purification method of the present invention can be integrated with the process that proceeds in the cassette.

After fluorine production and purification, fluorine is transported to the point of use. This preferably proceeds under a pressure higher than ambient pressure.

In a preferred embodiment, the fluorine is pressurized by a compressor, except that no pressurized gas is applied except for the fluorine element.

As expected, the storing step preferably refers to the step of storing the fluorine element in a suitable tank, for example, a stainless steel bottle.

The fluorine is preferably produced at a location where there is a point where it is used through electrolysis in a process chamber or an apparatus in fluid communication with the process chambers. This means that the produced fluorine element is not filled in the pressurized bottle or tank to be separated from the conveyance line thereafter. If desired, fluorine is stored only in bottles or tanks that remain connected to the transfer line. The fluorine generating device is often located less than 500 m from the same plant as the tool in which the fluorine generating device is used, i.e., the manufacturing tool; The generator will often be located, for example, near the tool, e.g., 100 m or less away from the tool. The fluorine generating device may even be located very close to the process chamber as a point where fluorine is used, for example the distance may be less than 10 m.

The transfer step preferably refers to the step of passing fluorine through a pipe, especially a pipe that is kept in a long connected state to prevent air from entering the fluorine and preventing fluorine from leaking from the manufacturing apparatus to the point of use.

In another aspect, the present invention also relates to an electrolytic cell for the production of a fluorine element by electrolysis of a molten HF adduct of KF, wherein the electrolytic cell (c) is provided with a fluorine capable of being connected to the hydrogen fluoride supply unit A hydrogen supply line (b) is mounted, and the hydrogen fluoride supply line (b) has a fluid orifice having an inner diameter of about 2.5 mm. The term " fluid orifice " and the nature and means for achieving said inner diameter have already been described in the paragraph on in the content of the method for supplying HF to the electrolytic cell to produce said fluorine element. The above description and description apply equally to embodiments of the present invention relating to electrolytic cells for the generation of fluorine elements by electrolysis of a molten HF adduct of KF.

In a preferred embodiment of the present invention relating to an electrolytic cell for the production of fluorine elements by electrolysis, the fluorine is produced from an electronic device selected from the group consisting of cassettes, preferably electronic devices, preferably semiconductors, photovoltaics, MEMS and TFT It is produced in cassettes for producing fluorine in "on-site" or "off-site" plants. The concept, properties and means for achieving "on-site" or "off-the-shelf" operation of a production plant are already described above in the context of a method for supplying HF to an electrolytic cell for the production of fluorine elements. The above description and description apply equally to embodiments of the present invention relating to electrolytic cells for the generation of fluorine elements by the electrolysis of molten HF adduct of KF.

In another preferred embodiment of the present invention relating to an electrolytic cell for the production of fluorine elements by electrolysis, the electrolytic cell has a capacity of producing 50 to 100 kg of fluorine (F ₂ ) per day (24 hours), preferably 24 Hour) fluorine (F ₂ ) production capacity of 80 kg to 100 kg and more preferably about 24 hours of fluorine (F ₂ ) production capacity of about 80 kg to 90 kg.

The following examples are intended to illustrate the invention without limiting it.

Example  1: gas in the electrolytic cell for the production of fluorine element HF A method of supplying

An electrolytic cell having a composition of approximately KF.2HF was filled in the electrolytic cell and heated to about 80 to 120 DEG C to melt the salt in the cell. The gas HF was introduced into the electrolytic cell through the HF feed line, in which the inside diameter of the fluid orifice was 2.5 mm and the HF feed rate per hour was about 8 kg / h. The automatic valve was adjusted to provide HF feed (kg) and feed spacing (h) at a feed rate of 3 kg / h to 4 kg / h of HF in terms of electrolytic cell production capacity. A voltage of 8 V to 10 V was applied, and the electrolytic salt composition dissolved in the hydrogen fluoride was passed through an electric current; The contents in the cell were maintained in the range of about 80 캜 to 100 캜. A fluorine element and a hydrogen element were formed in the respective electrode compartments. The resulting fluorine was passed through a Monel metal frit to remove solids, pressurized to about 10 Bar abs with a compressor, cooled to -80 ° C and passed through a trap; In this trap, the entrained HF was condensed. The gas F ₂ leaving the trap was passed through the NaF layer to remove any residual HF.

During the interval when the HF feed was stopped, N ₂ gas was pushed into the HF feed line to measure the electrolyte level. Depending on the measured electrolyte level, the HF feed was reduced, increased or kept constant.

The disclosures of any of the patents, patent applications and publications incorporated herein by reference thereto, when they are contrary to the description of the present invention to the extent that they may make any term ambiguous, Things should be prioritized.

Claims (18)

And a step of supplying fresh hydrogen fluoride as a feed material to the electrolytic cell (electrolytic cell) so as to supplement the consumed hydrogen fluoride (HF), electrolysis of HF contained in the electrolyte, which generates a fluorine element from the molten salt electrolyte A method for producing F ₂ in an electrolytic cell (electrolyzer) to produce a fluorine element (by electrolysis) from a molten salt electrolyte, wherein F ₂ and H ₂ are formed and the spent HF is fed (A) from a hydrogen fluoride feed unit, (b) through a hydrogen fluoride feed line, (c) to an electrolytic cell, wherein the supply of fresh HF is carried out in an HF flow rate (HF supply) process for producing a F ₂ in the electrolytic cell (electrolytic cell) will be the electrolyte per ton of HF 10 ㎏ / h is limited to be less. The process according to claim 1, wherein the molten salt electrolyte is hydrolyzed and the molten salt electrolyte is a molten HF adduct of KF, preferably a molten HF adduct of KF according to the formula KF (1.8-2.3) HF Way. 3. A method according to claim 1 or 2, wherein the hydrogen fluoride feed requirement relative to the fluorine production capacity of the electrolytic cell is in the range of 2 kg / h HF to 5 kg / h HF, Is in the range of 3 kg / h HF to 4 kg / h HF. 4. The process according to any one of claims 1 to 3, wherein the amount of HF feed per hour (kg / h) is less than 15 kg / h, more preferably less than 10 kg / h per 2 tonnes of electrolyte. 5. The method according to any one of claims 1 to 4, wherein the amount of HF feed per hour (kg / h) is in the range of 1 kg / h to 20 kg / h, preferably in the range of 1 kg / More preferably in the range of 1 kg / h to 10 kg / h. 6. The method according to claim 5, wherein the amount of HF feed per hour (kg / h) is in the range of 2 kg / h to 10 kg / h, preferably in the range of 4 to 10 kg / h, more preferably 6 kg / To 10 kg / h, even more preferably in the range of 7 kg / h to 9 kg / h, and most preferably the HF feed rate per hour is about 8 kg / h. 7. A method according to any one of claims 1 to 6, wherein the amount of HF feed per hour (kg / h) is reached by adjusting the HF flow rate by means of a pressure means or a pumping means. 8. The method according to any one of claims 1 to 7, wherein the amount of HF feed per hour (kg / h) is adjusted by adjusting the diameter of the fluid orifice in the hydrogen fluoride feed line (b), preferably within the hydrogen fluoride feed line Lt; RTI ID = 0.0 > 2.5 < / RTI > mm in diameter. The method according to claim 8, wherein the HF feed amount (kg) and the feed interval (h) are controlled by an automatic valve. 10. The method according to any one of claims 1 to 9, wherein HF is supplied via a supply line immersed in an electrolyte for a specified period of time, and after a certain period of time has elapsed after the supply is stopped, The electrolyte level is measured by measuring the pressure difference between the electrolyte level in the flooded line and the electrolyte level surrounding the flooded line and the cycle of such HF feed and electrolyte level measurement is repeated at least once Lt; / RTI > 11. The method according to any one of claims 1 to 10, wherein the fluorine element produced in the electrolytic cell (c) is intended to be used as a corrosive liquid or chamber cleaner in a method of manufacturing an electronic device, Way. 12. The method of claim 11, wherein the electronic device is selected from the group consisting of a semiconductor, a photovoltaic cell, a MEMS, and a TFT. The method according to claim 11 or 12, wherein fluorine is produced "on-site" or "off-site" with a production plant used in a method of manufacturing an electronic device. The method according to claim 1, further comprising the step of supplying F ₂ in the electrolytic cell (electrolytic cell) to produce a fluorine element (by electrolysis) from the molten salt electrolyte, comprising the step of supplying hydrogen fluoride as a feed material to the electrolytic cell The process comprises the steps of: (a) transferring hydrogen fluoride (HF) from a hydrogen fluoride feed unit to (b) an electrolytic cell via (c) a hydrogen fluoride feed line, wherein hydrogen fluoride The required amount of feed is supplied to the electrolytic cell, preferably as the gas HF, at a substantially lower HF feed rate (kg / h) per hour when compared to the maximum (maximum) HF feed capacity of the feed, The HF feed is equal to or less than 25% of the maximum (maximum) feed. 15. The method of claim 14, wherein the maximum (maximum) feed is equal to or less than 100 kg / h, preferably equal to or less than 80 kg / h. The electrolytic cell (c) is equipped with a hydrogen fluoride supply line (b) which can be connected to the hydrogen fluoride supply unit (a), and the hydrogen fluoride supply line The hydrogen fluoride supply line (b) has a fluid orifice having a diameter of about 2.5 mm. The method of claim 16, wherein the fluorine is generated in a cassette and is preferably " on-site " or " on-site " with a production plant of an electronic device, preferably an electronic device selected from the group consisting of semiconductors, photovoltaics, MEMS, Wherein the electrolytic cell is produced from a cassette for producing fluorine in an " off-site " Claim 16 or 18. The method of claim 17, 50 ㎏ to 100 ㎏ of days (24 hours), fluorine (F ₂₎ production capacity, preferably at 80 ㎏ to 100 ㎏ of days (24 hours), fluorine (F ₂₎ production capacity , More preferably about 80 kg to about 90 kg, of fluorine (F ₂ ) production capacity per day (24 hours).