WO2013092772A1 - Procédé d'introduction de fluorure d'hydrogène dans une cellule électrolytique - Google Patents

Procédé d'introduction de fluorure d'hydrogène dans une cellule électrolytique Download PDF

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Publication number
WO2013092772A1
WO2013092772A1 PCT/EP2012/076246 EP2012076246W WO2013092772A1 WO 2013092772 A1 WO2013092772 A1 WO 2013092772A1 EP 2012076246 W EP2012076246 W EP 2012076246W WO 2013092772 A1 WO2013092772 A1 WO 2013092772A1
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Prior art keywords
hydrogen fluoride
fluorine
electrolytic cell
electrolyte
feeding quantity
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PCT/EP2012/076246
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English (en)
Inventor
Holger Pernice
Peter M. Predikant
Oliviero Diana
Philippe Morelle
Harald Krueger
Christoph Sommer
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Solvay Sa
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Publication date
Application filed by Solvay Sa filed Critical Solvay Sa
Priority to CN201280070218.3A priority Critical patent/CN104126031A/zh
Priority to KR1020147019955A priority patent/KR20140108293A/ko
Publication of WO2013092772A1 publication Critical patent/WO2013092772A1/fr

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    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B1/00—Electrolytic production of inorganic compounds or non-metals
    • C25B1/01—Products
    • C25B1/24—Halogens or compounds thereof
    • C25B1/245—Fluorine; Compounds thereof
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B15/00—Operating or servicing cells
    • C25B15/02—Process control or regulation
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B15/00—Operating or servicing cells
    • C25B15/08—Supplying or removing reactants or electrolytes; Regeneration of electrolytes

Definitions

  • the invention concerns an improved method of supplying hydrogen fluoride as feed material to an electrolytic cell (electrolyzer) for the electrolytic generation of elemental fluorine.
  • this elemental fluorine is intended for the supply (delivery) in a method for the manufacture of electronic devices.
  • Hydrogen fluoride is useful notably as feed material for chemical manufacturing processes such as manufacture by electrolysis of molecular fluorine (F 2 ), useful for example as chamber cleaning gas in the semiconductor industry, and the manufacture of other fluorinated chemicals such as fluorinated hydrocarbons.
  • chemical manufacturing processes such as manufacture by electrolysis of molecular fluorine (F 2 ), useful for example as chamber cleaning gas in the semiconductor industry, and the manufacture of other fluorinated chemicals such as fluorinated hydrocarbons.
  • Elemental fluorine (F 2 ) has no GWP (Global Warming Potential) and no impact on the ozone layer. Elemental fluorine is useful as fluorinating agent, e.g. for the manufacture of polymers which are fluorinated on the surface, for the manufacture of fluorinated solvents especially for Li ion batteries, as chamber cleaning agent and etchant for the manufacture of electronic devices, especially semiconductors, photovoltaic cells, micro-electromechanical
  • MEMS microelectroscopic systems
  • TFTs thin film transistors for flat panel displays or liquid crystal displays
  • Fluorine can be used for etching of layers constituted of very different constitution, for example, for etching silicon containing layers or other layers of compounds which form volatile reaction products, e.g. tungsten.
  • Etching can be performed thermally or plasma-assisted.
  • chamber cleaning usually, during deposition processes performed in treatment chambers - often CVD chambers (chambers wherein layers are deposited on items via chemical vapor deposition, e.g. plasma- enhanced CVD, metal organic CVD or low pressure CVD) - undesired deposits form on the walls and on inner constructive parts of the chamber and must be regularly removed. This is achieved by treating the deposits thermally or plasma-enhanced with elemental fluorine as chamber cleaning agent.
  • CVD chambers chambers wherein layers are deposited on items via chemical vapor deposition, e.g. plasma- enhanced CVD, metal organic CVD or low pressure CVD
  • elemental fluorine as an etchant, but also when used as chamber cleaning agent, it is desirable that the elemental fluorine be very pure.
  • the intrusion of water, carbon dioxide, nitrogen and oxygen is considered as undesired.
  • Elemental fluorine can be produced by various methods but is often produced electrolytically, as mentioned already above, from hydrogen fluoride (HF) as feed material for the electrolysis and source of the elemental fluorine. In the presence of an electrolyte salt, HF releases fluorine if a voltage of at least 2.9 V is applied. Practically, the voltage is often kept in a range of 8 to 11 Volts.
  • HF hydrogen fluoride
  • KF-(1.8-2.3) HF is the preferred electrolyte salt.
  • HF is fed into the reactor containing the molten electrolyte salt, and F 2 is electrolytically formed from the HF according to the equation (1) by applying a voltage and passing electric current through the molten salt :
  • WO 2004/009873 discloses an apparatus and a method for generation of fluorine by the electrolysis of hydrogen fluoride.
  • the fluorine is produced by electrolysis from HF in a fluorine generating cassette.
  • the fluorine may be used in the manufacture of electronic devices, e.g. in the production of TFTs.
  • the apparatus comprises : a plurality of individual fluorine generating cassettes ; said individual fluorine generating cassettes being operably connected to a fluorine gas distribution system for the remote use and consumption of said fluorine gas ; said fluorine generating cassettes being individually isolatable from said gas distribution system and removable from the apparatus for remote maintenance.
  • a supply of liquid hydrogen fluoride is held in a tank.
  • a hydrogen fluoride vaporizer vaporizes liquid hydrogen fluoride from the tank and supplies it to the cassettes to maintain a constant concentration of electrolyte being composed of the molten HF adduct of KF as mentioned before.
  • the objective of the present invention is to provide an improved method of feeding HF into an electrolytic cell for generating fluorine, in particular for generating fluorine with minimized impurities and most preferably a high purity fluorine.
  • an objective of the present invention is to provide an improved method in which the temperature can be kept more homogenous, the composition of the electrolyte is more homogenous over room and time, and/or by which method the formation of undesired impurities in the fluorine can be minimized or prevented.
  • the objective of the invention is achieved by a modified HF feed into an electrolytic cell for generating fluorine as compared to the standard way of HF feeding in the state of the art.
  • the HF consumed in the electrolysis is compensated by adding the required amount of fresh HF in a more smooth way during longer intervals.
  • the word "smooth" is e.g. intended to mean less, potentially negative, interference with
  • the invention provides a method for the manufacture of F 2 in an electrolytic cell (electrolyzer) for (electrolytically) generating elemental fluorine from a molten salt electrolyte by electrolysis of HF contained in the electrolyte, wherein F 2 and H 2 are formed, and consumed HF is replenished with a supply of fresh HF generating elemental fluorine from a molten salt electrolyte comprising a step of supplying fresh hydrogen fluoride as feed material to the electrolytic cell (electrolyzer) to replenish consumed HF, which method comprises transferring hydrogen fluoride (HF) from (a) a hydrogen fluoride supply unit via (b) a hydrogen fluoride supply line to (c) to the electrolytic cell, wherein the supply of fresh HF is limited to an HF flow (HF feeding quantity) of at most 10 kg/h of HF per ton of electrolyte.
  • HF hydrogen fluoride
  • the present invention provides a method for the manufacture of F 2 by electrolysis of HF contained in an electrolyte wherein F 2 and H 2 are formed and consumed HF is replenished with a supply of fresh HF wherein the supply of fresh HF is limited to an HF flow of at most 10 kg/h of HF per ton of electrolyte.
  • the HF flow is limited to at most 5 kg/h of HF per ton of electrolyte.
  • HF flow is interchangeable with the term "HF feeding quantity per hour”.
  • the term "ton” in the frame of the present invention refers to metric tons.
  • the term “electrolytic cell” is interchangeable with the term “electrolyzer”.
  • the elemental fluorine is generated electrolytically.
  • the present invention provides the overall advantages that, despite the addition of HF into the electrolytic cell, the temperature in can be kept more easily in a desired preset range and that the composition of the electrolyte stays more homogenous over room and time, e.g. throughout the electrolytic cell including the HF feeding or entry area.
  • a further advantage is that formation of impurities can be minimized or prevented, thus yielding in fluorine which necessitates either only limited additional purification measures or yielding in fluorine with a purity that is ready for use in a process in which the fluorine shall be used.
  • the HF supply lines are constructed for a much higher flow of HF for replenishment.
  • supply lines are constructed such that up to 80 kg/h of HF could be introduced into the electrolytic apparatus. According to the invention, the maximal HF flow is considerably lower.
  • the invention particularly concerns a method for supplying hydrogen fluoride as feed material to an electrolytic cell (electrolyzer) for (electrolytically) generating elemental fluorine from a molten salt electrolyte, which comprises transferring hydrogen fluoride (HF) from (a) a hydrogen fluoride supply unit via (b) a hydrogen fluoride supply line to (c) to the electrolytic cell, wherein the required amount of hydrogen fluoride feed for a defined fluorine production capacity is fed into the electrolytic cell with a substantially lower, preferably gaseous, HF feeding quantity per hour (kg/h) over a prolonged feeding interval compared to a full (maximum) HF feeding capacity of 80 kg/h of the supply line and the related short full HF feeding interval, e.g. short full HF feeding interval as applied in hitherto conventional methods).
  • HF hydrogen fluoride
  • the hydrogen fluoride (HF) can be added to the electrolytic cell either as a liquid HF feed or as a gaseous HF feed.
  • "Hydrogen fluoride” (HF) is understood to denote in particular anhydrous hydrogen fluoride.
  • the hydrogen fluoride is generally liquid.
  • the HF can be directly draw in the required quantity from the storage container and be transferred through the supply line (b) into the electrolytic cell (c), e.g. by pumping or simply by applying pressure to the container and pressing the HF into the supply line.
  • the storage container is additionally equipped with an evaporator, and the liquid HF then is evaporated from the storage container (a) and transferred through the supply line (b) into the electrolytic cell (c).
  • liquid HF feed is chosen, precaution must be taken to avoid a blockage (plugging) of the supply line by incidental freezing of the molten electrolyte salt in the HF outlet area which is reaching into the electrolyte in the electrolytic cell.
  • a flow orifice with an inner diameter of about 0.3 mm plugging may be observed.
  • Further precaution must be taken in the case of liquid HF feed to avoid potential disturbance of the electrolyte surface.
  • the method may be operated at a flow orifice with an inner diameter of about 0.35 mm, optionally with further adaptation of other process parameters.
  • a gaseous HF feed is chosen for the HF feeding into the electrolytic cell.
  • the invention concerns in consequence a method for supplying hydrogen fluoride as feed material to an electrolytic cell (electrolyzer) for (electrolytically) generating elemental fluorine from a molten salt electrolyte, which comprises transferring hydrogen fluoride (HF) from (a) a hydrogen fluoride supply unit via (b) a hydrogen fluoride supply line to (c) to the electrolytic cell, wherein the required amount of hydrogen fluoride feed for a defined fluorine production capacity is fed as gaseous HF into the electrolytic cell with a substantially lower HF feeding quantity per hour (kg/h) over a prolonged feeding interval compared to a full (maximum) HF feeding capacity, wherein the substantially lower HF feeding quantity is equal to or lower than 25 % of the full (maximum) feeding quantity.
  • the invention concerns a method for supplying hydrogen fluoride
  • full (maximum) feeding quantity of the supply line is 80 kg/h and includes a related short full HF feeding interval, e.g. short full HF feeding interval as applied in hitherto conventional methods.
  • the improved method of HF feeding is related to the manufacturing of elemental fluorine.
  • Elemental fluorine in the context of the invention is produced by electrolysis using hydrogen fluoride (HF) as feed material for the electrolysis and source of the elemental fluorine.
  • HF hydrogen fluoride
  • HF releases fluorine if a voltage of at least 2.9 V is applied. Practically, the voltage is often kept in a range of 8 to 10 or 11 Volt.
  • HF is advantageously supplied such that the level of electrolyte salt and HF in the respective cell does not exceed specific upper and lower levels.
  • the electrolytic cell also includes sensors which determine the temperature in the cell, the level of liquid in the cell or cells, the pressures and pressure differences, the anode currents and voltages and gas temperatures.
  • the cells are cooled with cooling water having a temperature of about 80 to 95°C.
  • a molten HF adduct of KF preferably having the formula KF-(1.8-2.3) HF
  • HF is fed into the reactor containing the molten electrolyte salt
  • F 2 is electro lytically formed from the HF according to the above equation (1) by applying a voltage and passing electric current through the molten salt.
  • the invention concerns a method for supplying hydrogen fluoride, wherein the molten salt electrolyte is a molten HF adduct of KF, preferably a molten HF adduct of KF with a range of HF according to the formula KF-(1.8-2.3) HF.
  • the invention concerns a method for supplying hydrogen fluoride, wherein the required amount of hydrogen fluoride feed related to the fluorine production capacity of the electrolytic cell is in the range of a HF feeding quantity of 2-5 kg/h HF, preferably in the range of 3-4 kg/h HF in view of an apparatus having a capacity of 2 tons electrolyte.
  • the invention concerns a method for supplying hydrogen fluoride, wherein the HF feeding quantity per hour (kg/h) is below 20 kg/h, preferably below 15 kg/h, and more preferably below 10 kg/h, to an apparatus having a capacity of 2 tons of electrolyte.
  • the HF feeding quantity per hour (kg/h) is in the range of 1-20 kg/h, preferably in the range of 1-15 kg/h, and more preferably in the range of 1-10 kg/h per 2 tons of electrolyte.
  • the HF feeding quantity per hour is in the range of 2-10 kg/h, preferably in the range of 4-10 kg/h, and more preferably in the range of 6-10 kg/h, and even more preferably in the range of 7-9 kg/h, and most preferably the HF feeding quantity per hour is about 8 kg/h per 2 tons of electrolyte.
  • the word "about” has the meaning that HF feeding quantity per hour can slightly vary around the value of 8 kg/h, e.g. being somewhat lower or somewhat higher than 8 kg/h. Thus the value may vary by about ⁇ 0.5 kg/h, and consequently the HF feeding quantity then is preferably 8 ⁇ 0.5 kg/h.
  • the HF feeding quantity per hour (kg/h) as described before can be achieved by several means.
  • the HF feeding quantity per hour (kg/h) is achieved by adjusting the HF flow rate by means of pressure or pumping means.
  • the HF feed line may have an orifice to reduce the flow of HF.
  • the preferred diameter of the orifice is in the range of 1 mm to 1 cm. The diameter should correlate to the amount of HF consumed per time unit.
  • the tube (liquid level sensing tube) reaching into the electrolytic bath (electrolyte) is characterized by a flow orifice in the tube of about 2.5 mm (inner) diameter.
  • the term "about” in this context means that the value of 2.5 mm may slightly vary, e.g. of at maximum
  • the flow orifice diameter may be characterized by as follows : 2.5 ⁇ 0.25 mm, 2.5 ⁇ 0.2 mm, or 2.5 ⁇ 0.1 mm, and the like. It has to be noted that the orifice may vary depending on the amount of HF to be supplied per hour and the inlet pressure of the HF. For an hourly supply of more HF than below 20 kg/h, an orifice with larger diameter may be useful. For the supply of HF at a much lower rate than e.g. 6 kg/h, an orifice with a smaller diameter may be advantageous.
  • the cross sectional area is approximately 5 mm 2 .
  • the cross sectional area should correlate to the amount of HF which is passed through it per hour.
  • the relation between HF feed per hour and cross sectional area is assumed to be linear. It is assumed that if the amount of HF per hour is doubled, an orifice with a cross sectional area which also is twofold greater should be used. It is assumed that orifices with a diameter in the range of from 1 mm to 1 cm can be applied in supply lines. Nevertheless, orifices with a smaller or greater diameter could be used, too if necessary.
  • the HF is fed as gas into the electrolytic cell and the HF feeding quantity per hour (kg/h) is achieved by adjusting the diameter of the flow orifice in the hydrogen fluoride supply line (b), preferably by means of a flow orifice in the hydrogen fluoride supply line (b) of about 2.5 mm inner diameter.
  • flow orifice means that the hydrogen fluoride supply line, which itself in the section from the HF storage container to the location of the flow orifice and again thereafter in the section reaching into the electrolyte may have, and usually will have, a greater inner diameter than said 2.5 mm of the flow orifice.
  • the inner diameter of such an HF supply line with an inner diameter of greater than said 2.5 mm before and after the flow orifice is reduced to a diameter of 2.5 mm at a location of the ending section of the HF supply line which is reaching into the electrolyte.
  • This reduction of the inner diameter of the HF supply line may be achieved in the broadest sense by any suitable constructive means to reduce the inner diameter at a single point inside of a pipe, to result in an orifice with the required diameter.
  • the method for supplying hydrogen fluoride is characterized in that the HF feeding quantity (kg) and feeding interval (h) is regulated by an automatic valve.
  • this automatic valve operates under preset conditions, optionally under modifying the HF feed parameters as appropriate from time to time during the process of manufacturing the fluorine, depending on the overall condition in the electrolytic cell as the electrolysis proceeds over time, e.g. depending on the temperature, the HF content, the level of the electrolyte, the current or any other relevant parameter in the electrolysis of the molten salt electrolyte, or the quality of the generated fluorine.
  • the maximally possible HF flow per hour is greater than the total consumption of HF per hour.
  • the HF flow is 6 to 10 kg/h, and the HF consumed is 2 to 6 kg/h.
  • the HF supply flow per hour may be greater than the actual consumption, and thus, the supply of HF can be interrupted for a certain time range.
  • the electrolyte level is determined during the time when no HF is supplied. The electrolyte level can, for example, be measured in a manner as described in the following paragraphs.
  • the HF supply line submerges into the molten electrolyte.
  • the level of electrolyte in the submerged part of the supply line and the level of electrolyte surrounding the submerged line are essentially identical.
  • the pressure of the inert gas prevents ingression of molten electrolyte.
  • the pressure of the inert gas must be higher or lower to prevent ingression of the electrolyte into the submerged line. It is possible to calibrate the pressure needed to prevent ingression of electrolyte, relative to the level of electrolyte in the cell.
  • the supply of HF can be regulated : if the level of electrolyte is comparably low, the HF flow may be regulated to a higher value, and/or the supply time may be extended ; and, if the level is comparably high, the HF flow may be regulated to a lower value, and/or the supply time may be shortened.
  • the ratio of HF flow in kg per hour and the HF consumption in kg per hour is between 1.2: 1 and 4 to 1. Preferably, it is between 1.5: 1 and 3: 1.
  • the electrolyte level is determined as mentioned above by introducing an inert gas into the supply line. It is preferred to have a rather high frequency of HF supply and electrolyte level determination. For example, up to 30 periods of HF supply and correspondingly, up to 30 periods of electrolyte level determination can be foreseen per hour.
  • HF supply would last for 33 seconds, followed by 27 seconds for making the level determination, followed by 33 seconds of HF supply, followed by 27 seconds of level determination and so on.
  • 30 seconds of HF supply would be interrupted for 30 seconds to determine the electrolyte level and so on.
  • the expert can predetermine the duration of HF supply and level determination according to his will. The higher the frequency of HF feed and a period of non-delivery of HF, the smoother is the operation of F 2 production.
  • the periods of HF feed last for e.g. 1 to 60 minutes,
  • intervals are practically useful intervals ; preferably shorter intervals can be chosen, e.g. intervals of 1 to 5 minutes, preferably 1 to 4 minutes, more preferably 1 to 3 minutes, and even more preferably 1 to 2 minutes, and most preferably an interval of about one minute, are very recommendable. If the period is measured in seconds, still shorter intervals of e.g. 1 to 60 seconds, 1 to 50 seconds, preferably 20 to 50 seconds, 1 to 40 seconds, preferably 20 to 40 seconds, 1 to 30 seconds, preferably about 30 seconds, 1 to 20 seconds, or 1 to 10 seconds are practically useful and recommendable intervals ; even shorter intervals can be chosen, e.g. intervals of 1 to 5 seconds, 1 to 4 seconds, 1 to 3 seconds, 1 to 2 seconds, and an interval of about one second, but these very short intervals are less preferred.
  • the periods on non-delivery of HF correspond to the remaining time during operation of the plant.
  • the pressure determination can be performed in the F 2 compartment of the cell or in the H 2 compartment. If it is performed in the F 2 compartment (which is preferred), N 2 or F 2 are preferred inert gases. If it is performed in the H 2 compartment (which is preferred), N 2 or H 2 are preferred inert gases.
  • N 2 or any other inert gas e.g. a noble gas, can be passed through the HF line or lines to prevent from molten electrolyte to flow into the line or lines.
  • the HF may supplied from any type of hydrogen fluoride storage containers.
  • the hydrogen fluoride storage container can be a single hydrogen fluoride storage containers of varying sizes or it can be a hydrogen fluoride storage unit comprising a plurality of fixed or optionally transportable hydrogen fluoride storage containers which may be connected through a hydrogen fluoride supply line with the electrolyzer.
  • the invention particularly is suitable in a process for the manufacture of fluorine, which involves the supply of hydrogen fluoride to a plant, which comprises (i) filling at least one transportable hydrogen fluoride storage container with hydrogen fluoride, (ii) transporting the hydrogen fluoride storage container to the hydrogen fluoride supply unit, (iii) connecting the hydrogen fluoride storage container to the hydrogen fluoride supply line and (iv) supplying hydrogen fluoride from the hydrogen fluoride storage container to the hydrogen fluoride supply line.
  • an evaporator for evaporation of liquid HF is provided with the hydrogen flurried storage container or such an evaporator for evaporation of liquid HF is locally available at the plant where the HF is to be provided for the manufacture of fluorine, and can be connected to the hydrogen fluoride storage container or unit and to the hydrogen fluoride supply line.
  • additional means e.g. safety means like an HF sensor, an HF destruction system may be present at the location of the hydrogen fluoride storage container or unit, too.
  • the HF storage containers used in the invention comprise an automatic HF level sensor.
  • the HF storage containers can be installed on weighing scales.
  • a process control system in particular an automatic process control system is operable to close the remotely controlled valve of a first, empty HF container and to open the remotely controlled valve of another second HF-containing hydrogen fluoride storage container. This embodiment is particularly effective to avoid manual handling of HF valves and to ensure a continuous HF supply.
  • valves are operable to close automatically in case of anomal operation state, such as for example a process interruption in a process-equipment connected to the HF supply line.
  • valves are operable to close automatically in case of an HF leakage in the hydrogen fluoride supply unit according to the invention.
  • HF leakage can for example be caused by a leakage of optional flange-connections inside the HF storage container. This avoids in particular the necessity to approach the hydrogen fluoride supply unit in this case.
  • hydrogen fluoride supply unit suitably further comprises at least one interspace vent valve in connection with one or more closed isolation space.
  • the interspace vent valve is generally operable to remove optionally present hydrogen fluoride from the closed isolation space. Removal can be carried out, for example, by applying vacuum. In another aspect, removal can be carried out, for example, by flushing the closed isolation space with an inert gas and/or a pressurized purging gas such as for example anhydrous air or, preferably, nitrogen. In one aspect, the removal is carried continuously.
  • the removal is carried out discontinuously, in particular when an HF storage container is connected to and/or disconnected from the supply line.
  • gases recovered from the closed isolation space are suitably vented to an HF destruction unit, for example a scrubber.
  • the method for supplying hydrogen fluoride for the electrolytic manufacture of fluorine is characterized in that the elemental fluorine generated in the electrolytic cell (c) is intended for the use in a method for the manufacture of electronic devices, preferably for the use as an etchant or use as a chamber cleaning agent in a method for the manufacture of electronic devices.
  • the method for supplying hydrogen fluoride for the electrolytic manufacture of fluorine is characterized in that the electronic devices are selected from the group consisting of semiconductors, photovoltaic cells, MEMS, and TFTs.
  • the fluorine is used as chamber cleaning agent and etchant for the manufacture of electronic devices, especially semiconductors, photovoltaic cells, micro-electromechanical systems ("MEMS"), TFTs (thin film transistors for flat panel displays or liquid crystal displays), and the like.
  • MEMS micro-electromechanical systems
  • TFTs thin film transistors for flat panel displays or liquid crystal displays
  • Fluorine can be used for etching of layers constituted of very different constitution, for example, for etching silicon containing layers or other layers of compounds which form volatile reaction products, e.g. tungsten. Etching can be performed thermally or plasma- assisted.
  • chamber cleaning usually, during deposition processes performed in treatment chambers - often CVD chambers (chambers wherein layers are deposited on items via chemical vapor deposition, e.g.
  • plasma-enhanced CVD metal organic CVD or low pressure CVD
  • undesired deposits form on the walls and on inner constructive parts of the chamber and must be regularly removed. This is achieved by treating the deposits thermally or plasma-enhanced with elemental fluorine as chamber cleaning agent.
  • the elemental fluorine generated according to the present invention meets these quality requirements, as already explained in more detail above.
  • the method for supplying hydrogen fluoride for the electrolytic manufacture of fluorine is characterized in that the fluorine is generated "on site" or "over the fence" of a production plant for use in the method for the manufacture of electronic devices.
  • the fluorine can be manufactured, if desired, on site. This is a preferred embodiment of the invention. It can be produced in one or more satellite plants, e.g. in a fluorine generating cassette as described in WO 2004/009873. If desired, each cassette can be allocated to one or more process chambers wherein etching is performed ; or a plurality of fluorine generating cassettes is connected to a fluorine gas distribution system which is connected to the chambers.
  • the inventive method for the low temperature purification can be integrated into the cassette.
  • the fluorine is delivered to the point of use. This is preferably performed under a pressure which is greater than ambient pressure.
  • the fluorine is pressurized by means of compressors, and no pressurizing gas is applied, unless elemental fluorine.
  • the step of storage if foreseen, preferably denotes the storage of the elemental fluorine in suitable tanks, e.g. stainless steel bottles.
  • the fluorine is preferably generated on site of its point of use via electrolysis in an apparatus which is in fluid communication with the process chamber or process chambers. This means that the generated elemental fluorine is not filled into a tank or into pressurized bottles, which are then disconnected from the delivery line. If desired, the fluorine is stored in tanks or bottles only which remain connected to the delivery line.
  • the fluorine generator is located on the same plant as the tools wherein it is used, i.e. in a distance of less than 500 m from the manufacturing tools ; the generator often will be located near the tools, e.g. in a distance of 100 m or less from the tools. They can even be located in close proximity to the process chamber as the point of use, e.g. the distance can be 10 m or less.
  • the step of delivery preferably denotes passing the fluorine from the manufacturing apparatus to the point of use through pipes, especially through pipes which remain permanently connected to prevent intrusion of air into the fluorine, and to prevent fluorine to leak out.
  • the invention also concerns an electrolytic cell for the generation of elemental fluorine by the electrolysis of a molten HF adduct of KF, wherein the electrolytic cell (c) is equipped with (b) a hydrogen fluoride supply line which can be connected a the hydrogen fluoride supply unit (a), and wherein the hydrogen fluoride supply line (b) has a flow orifice of about 2.5 mm inner diameter.
  • flow orifice and the nature and means to achieve said inner diameter are already described above in the context of the method of supplying HF to an electrolysis cell for the manufacture of elemental fluorine. Said description and explanations given above equally apply to this aspect of the invention which concerns an electrolytic cell for the generation of elemental fluorine by the electrolysis of a molten HF adduct of KF.
  • an electrolytic cell for the generation of elemental fluorine by the electrolysis the fluorine is generated in a cassette, preferably in a cassette for producing fluorine "on site” or “over the fence” of production plants for electronic devices, preferably for electronic devices selected from the group consisting of semiconductors, photovoltaic cells, MEMS, and TFTs.
  • the concept and nature and means to achieve "on site” or “over the fence” of production plants are already described above in the context of the method of supplying HF to an electrolysis cell for the manufacture of elemental fluorine. Said description and explanations given above equally apply to this aspect of the invention which concerns an electrolytic cell for the generation of elemental fluorine by the electrolysis of a molten HF adduct of KF.
  • an electrolytic cell for the generation of elemental fluorine by the electrolysis the fluorine by the electrolysis of a molten HF adduct of KF, is provided for a daily (24 h) production capacity of 50 to 100 kg fluorine (F 2 ), preferably a daily (24 h) production capacity of 80 to 100 kg fluorine (F 2 ), and more preferably a daily (24 h) production capacity of about 80 to 90 kg fluorine (F 2 ).
  • Example 1 Feeding gaseous HF into an electrolytic cell for the manufacture of elemental fluorine
  • An electrolyte salt with a composition of about KF-2HF is filled into an electrolysis cell, heated to about 80 - 120°C and molten therein.
  • Gaseous HF is introduced into the electrolytic cell through an HF supply line wherein the inner diameter of the flow orifice is 2.5 mm and with a HF feeding quantity per hour of about 8 kg/h.
  • the HF feeding quantity (kg) and feeding interval (h) is regulated by an automatic valve to provide a feed of 3 to 4 kg/h HF in view of the production capacity of the electrolytic cell.
  • a voltage of between 8 to 10 V is applied, and current is passed through the composition of electrolyte salt dissolved in the hydrogen fluoride ; the content of the cell is kept in a range of about 80 to 100°C.
  • the generated elemental fluorine is passed through a Monel metal frit to remove solids and pressurized by means of a compressor to about 10 Bar abs. and then passed through a trap cooled to -80°C ; in this trap, entrained HF condenses.
  • the gaseous F 2 leaving the trap is and passed through a bed of NaF to remove any residual HF.
  • the electrolyte level is determined by pressing N 2 gas into the HF supply line. Depending on the determined electrolyte level, the supply of HF is reduced, increased or kept constant.

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  • Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)

Abstract

L'invention concerne un procédé d'introduction de fluorure d'hydrogène comme matière d'alimentation dans une cellule électrolytique (électrolyseur) pour générer (de manière électrolytique) du fluor élémentaire à partir d'un électrolyte à sel fondu, qui comprend le transfert de fluorure d'hydrogène (HF) depuis (a) une unité d'alimentation en fluorure d'hydrogène par (b) une ligne d'alimentation en fluorure d'hydrogène vers (c) la cellule électrolytique, la quantité requise d'alimentation en fluorure d'hydrogène pour une capacité définie de production de fluorure étant introduite dans la cellule électrolytique, de préférence sous forme de HF gazeux, avec une quantité d'alimentation en HF par heure (kg/h) pendant un intervalle d'alimentation prolongé sensiblement inférieur par comparaison avec une capacité d'alimentation en HF totale (maximale) de 80 kg/h de la ligne d'alimentation et au court intervalle d'alimentation en HF total lié, comme dans les procédés classiques connus jusqu'à présent. Un autre aspect de l'invention concerne également une cellule électrolytique pour la génération de fluor élémentaire par l'électrolyse d'un composé d'addition de HF fondu de KF, la ligne d'alimentation en HF étant adaptée au procédé pour introduire du fluorure d'hydrogène comme matière d'alimentation selon l'invention.
PCT/EP2012/076246 2011-12-22 2012-12-19 Procédé d'introduction de fluorure d'hydrogène dans une cellule électrolytique WO2013092772A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
CN201280070218.3A CN104126031A (zh) 2011-12-22 2012-12-19 将氟化氢送入电解池中的方法
KR1020147019955A KR20140108293A (ko) 2011-12-22 2012-12-19 플루오르화수소를 전해 셀에 공급하는 방법

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EP11195430 2011-12-22
EP11195430.1 2011-12-22

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WO2013092772A1 true WO2013092772A1 (fr) 2013-06-27

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4125443A (en) * 1976-10-19 1978-11-14 British Nuclear Fuels Ltd. Electrolytic production of fluorine
WO2004007802A2 (fr) * 2002-07-11 2004-01-22 L'air Liquide, Societe Anonyme A Directoire Et Conseil De Surveillance Pour L'etude Et L'exploitation Des Procedes Georges Claude Appareil de production de gaz fluore
WO2004009873A1 (fr) 2002-07-19 2004-01-29 The Boc Group Plc Dispositif et procede de production de fluor
EP1422319A2 (fr) * 2002-11-20 2004-05-26 Toyo Tanso Kabushiki Kaisya Générateur de fluor gazeux
US20040151656A1 (en) * 2001-11-26 2004-08-05 Siegele Stephen H. Modular molecular halogen gas generation system

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20030121796A1 (en) * 2001-11-26 2003-07-03 Siegele Stephen H Generation and distribution of molecular fluorine within a fabrication facility
KR100515412B1 (ko) * 2003-01-22 2005-09-14 도요탄소 가부시키가이샤 용융염 전해장치

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4125443A (en) * 1976-10-19 1978-11-14 British Nuclear Fuels Ltd. Electrolytic production of fluorine
US20040151656A1 (en) * 2001-11-26 2004-08-05 Siegele Stephen H. Modular molecular halogen gas generation system
WO2004007802A2 (fr) * 2002-07-11 2004-01-22 L'air Liquide, Societe Anonyme A Directoire Et Conseil De Surveillance Pour L'etude Et L'exploitation Des Procedes Georges Claude Appareil de production de gaz fluore
WO2004009873A1 (fr) 2002-07-19 2004-01-29 The Boc Group Plc Dispositif et procede de production de fluor
EP1422319A2 (fr) * 2002-11-20 2004-05-26 Toyo Tanso Kabushiki Kaisya Générateur de fluor gazeux

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CN104126031A (zh) 2014-10-29
KR20140108293A (ko) 2014-09-05

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