Apparatus for recovering unreacted NAF generated during PF3 manufacturing process
The apparatus addresses the challenge of recovering unreacted NaF in PF3 manufacturing by utilizing a multi-unit process to separate and purify NaF, achieving high purity and yield, thus optimizing the PF3 production process and reducing costs.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- POHANG IRON & STEEL CO LTD
- Filing Date
- 2025-12-22
- Publication Date
- 2026-06-25
AI Technical Summary
Current methods for manufacturing phosphorus trifluoride (PF3) face challenges in achieving high purity and large-scale synthesis due to the difficulty in recovering and regenerating unreacted sodium fluoride (NaF), leading to increased production costs and inefficient processes.
An apparatus is developed to recover unreacted NaF by including a PF3 manufacturing unit, a NaF separation unit, and a NaF recovery unit, which involves heating, filtering, and drying processes to separate and purify NaF, along with a byproduct recovery unit to condense and store byproducts like PCl3 and AN.
The apparatus efficiently recovers NaF with a high recovery rate of 97% purity and 96% yield, enhancing the efficiency and reducing the costs of the PF3 manufacturing process.
Smart Images
Figure KR2025022442_25062026_PF_FP_ABST
Abstract
Description
Device for recovering unreacted NAF generated during the manufacturing process of PF3
[0001] The present disclosure relates to an apparatus for recovering unreacted NaF generated during the process of manufacturing phosphorus trifluoride (PF3).
[0002] As the demand for high-performance memory semiconductors continues to increase, there is a growing demand for processes that are more advanced than the current 7th generation process. Conventional etching gases exhibit a significant difference in the Bottom:Top ratio as the height increases, making it difficult to manufacture high-layer memory. However, the newly selected PF3 suppresses the chemical reaction of radicals at low temperatures, and P forms a protective film on the wafer surface, enabling narrower and deeper etching compared to existing etching gases. Consequently, efforts are being made to replace conventional gases with PF3, but it is currently difficult to achieve high purity and large-scale synthesis suitable for semiconductor processes.
[0003] PF3 has been studied as an intermediate in the synthesis step of LiPF6, which is used as an electrolyte in conventional lithium-ion batteries, but research on the synthesis of PF3 has been very limited as it proceeds as a one-step process without separate purification or separation. Generally, PF3 and HCl can be obtained by reacting PCl3 with HF, and PF3 and metal chlorides can be obtained by reacting PCl3 with metal fluoride materials such as NaF or ZnF2.
[0004] A method was developed to obtain PF3 and solid NaCl by reacting PCl3 with NaF, which is a low-risk raw material compared to HF, as a fluoride raw material, but this method has the disadvantage that the reaction is very slow and the conversion rate is low.
[0005] In conventional methods, an excess amount of NaF was added at a level of 3 to 10 times the equivalent weight to increase the conversion rate of PCl3. As a result, although the conversion rate of PCl3 could be increased to over 90%, there was a problem that the production cost increased due to the disposal costs of unreacted NaF remaining after the reaction caused by the excess addition.
[0006] However, there is currently little research being conducted on separate methods or devices for recovering unreacted NaF generated during the process of manufacturing PF3, and therefore, further research is needed on methods to recover and regenerate unreacted NaF generated during PF3 manufacturing.
[0007] One aspect of the present invention for solving the aforementioned problem is to provide an apparatus for recovering unreacted NaF generated during the process of manufacturing phosphorus trifluoride, which can efficiently recover unreacted NaF generated during the process of manufacturing phosphorus trifluoride and increase the recovery rate.
[0008] Another aspect of the present invention for solving the aforementioned problem is to provide an apparatus for recovering unreacted NaF generated during the process of manufacturing phosphorus trifluoride, which can contribute to maximizing the efficiency of the phosphorus trifluoride manufacturing process and reducing process costs.
[0009] An apparatus for recovering unreacted NaF generated during the process of manufacturing PF3 according to the concept of the present disclosure may include: a PF3 manufacturing unit that produces PF3 by reacting NaF with a substance containing P; a NaF separation unit that separates the remaining NaF after producing the PF3 into insoluble NaF and a mixed gas; and a NaF recovery unit that recovers NaF by filtering and drying the insoluble NaF.
[0010] The above NaF separation unit heats the remaining NaF to produce a mixed gas containing at least one of PCl3 and AN, and the device for recovering unreacted NaF generated during the process of manufacturing PF3 may further include a byproduct recovery unit that recovers at least one of PCl3 and AN by condensing the mixed gas to a predetermined temperature.
[0011] The above NaF separation unit can heat the remaining NaF at 70°C to 150°C for 4 to 12 hours.
[0012] The above byproduct recovery unit can condense the above mixed gas at 5°C to 30°C and store it in a storage tank.
[0013] The above NaF separation unit can separate the insoluble NaF and the Na salt by providing H2O to the insoluble NaF and stirring with an impeller equipped with spiral blades.
[0014] The device for recovering unreacted NaF generated during the process of manufacturing the above PF3 may further include a wastewater tank for storing the remaining aqueous solution excluding the NaF filtered in the above NaF recovery unit.
[0015] The ratio of NaF to H2O based on the weight percentage of the remainder of NaF may be 1:0.5 to 1:1.5.
[0016] The remaining aqueous solution, excluding the above NaF, may include at least one of NaCl, HF, and HCl.
[0017] The above NaF recovery unit can dry the insoluble NaF and then purge it with an inert gas.
[0018] According to the present invention, an apparatus for recovering unreacted NaF generated during the process of manufacturing phosphorus trifluoride can be provided, which can efficiently recover unreacted NaF generated during the process of manufacturing phosphorus trifluoride and increase the recovery rate.
[0019] In addition, according to the present invention, an apparatus for recovering unreacted NaF generated during the process of manufacturing phosphorus trifluoride can be provided, which can contribute to maximizing the efficiency of the phosphorus trifluoride manufacturing process and reducing process costs.
[0020] The effects obtainable from the present invention are not limited to those mentioned above, and other unmentioned effects will be clearly understood by those skilled in the art to which the present invention belongs from the description below.
[0021] FIG. 1 is a schematic diagram illustrating the configuration of a device for recovering unreacted NaF generated during the process of manufacturing PF3 according to one embodiment of the present invention.
[0022] FIG. 2 is a schematic diagram illustrating the configuration of a device for recovering unreacted NaF generated during the process of manufacturing PF3 according to another embodiment of the present invention.
[0023] Throughout the specification, the same reference numerals refer to the same components. This specification does not describe all elements of the embodiments, and general content in the art to which the invention pertains or content that overlaps between embodiments is omitted. The terms 'part, module, component, block' used in the specification may be implemented in software or hardware, and depending on the embodiments, a plurality of 'parts, modules, components, blocks' may be implemented as a single component, or a single 'part, module, component, block' may include a plurality of components.
[0024] Throughout the specification, when a part is described as being "connected" to another part, this includes not only cases where they are directly connected but also cases where they are indirectly connected, and indirect connections include connections made via a wireless communication network.
[0025] Furthermore, when it is stated that a part "includes" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components.
[0026] Throughout the specification, when it is stated that a component is located "on" another component, this includes not only cases where a component is in contact with another component, but also cases where another component exists between the two components.
[0027] The terms first, second, etc. are used to distinguish one component from another, and the components are not limited by the aforementioned terms.
[0028] Singular expressions include plural expressions unless there is an obvious exception in the context.
[0029] In each step, identification codes are used for convenience of explanation and do not describe the order of the steps; the steps may be performed differently from the specified order unless the context clearly indicates the characteristic sequence.
[0030] The term “and / or” may include a combination of multiple related described components or any of the multiple related described components.
[0031] The operating principle and embodiments of the present invention will be described below with reference to the attached drawings.
[0032] FIG. 1 illustrates the configuration of a device for recovering unreacted NaF generated during the process of manufacturing PF3 according to one embodiment of the present invention, and FIG. 2 illustrates the configuration of a device for recovering unreacted NaF generated during the process of manufacturing PF3 according to another embodiment of the present invention.
[0033] As illustrated in FIGS. 1 and 2, the device for recovering unreacted NaF generated during the process of manufacturing PF3 according to the present embodiment may include a PF3 manufacturing unit (1), a NaF separation unit (10), and a NaF recovery unit (40).
[0034] The PF3 manufacturing unit (1) can produce PF3 by reacting a substance containing P with NaF. Here, the substance containing P can be a phosphorus chloride compound such as PCl3. Below, an example using PCl3 as an example of a substance containing P will be described.
[0035] The NaF separation unit (10) can receive and process unreacted material from a reaction that generates PF3 gas using PCl3, AN (acetonitrile), and NaF. The NaF separation unit (10) can heat the mixture received from the PF3 manufacturing unit (1) to produce a mixed gas containing at least one of PCl3 and AN (acetonitrile), and then add an excess amount of distilled water and stir with an impeller (11) to dissolve impurities such as NaCl, HF, and HCl.
[0036] The above NaF separation part (10) may be formed to be long in the longitudinal direction. However, since this is a simplified illustration in the drawing for the sake of simplification of description, the shape of the NaF separation part (10) is not limited by the dimensional ratio in the drawing.
[0037] The above NaF separation unit (10) may include an impeller (11) for stirring the mixture of the unreacted material and the NaF after reaction.
[0038] The above impeller (11) is composed of a shaft (12) that rotates around the length direction and a spiral blade (13) that rotates together with the rotation of the shaft (12), and the shaft (12) of the impeller (11) can be connected to an externally installed motor.
[0039] The above impeller (11) may be installed such that the lower part of the spiral blade (13) maintains a predetermined distance from the bottom surface inside the NaF separation section (10). Since the larger the distance between the spiral blade (13) and the bottom surface of the NaF separation section (10), the more unreacted material accumulates without being stirred, it may be desirable to maintain an appropriate distance between the spiral blade (13) and the bottom surface of the NaF separation section (10). The shaft (12) of the above impeller (11) may be a rigid structure such as a metal bar, or a flexible structure such as a wire rope.
[0040] One or more of the spiral wings (13) may be installed on the shaft (12), and the spiral wings (13) may be installed at regular intervals around the shaft (12) so as not to interfere with the rotation of each wing during stirring.
[0041] In addition, as shown in FIG. 2, the NaF separation unit (10) can be installed in multiple units, and multiple NaF separation units (10) can be installed in series or in parallel. By installing two or more NaF separation units (10), high-purity NaF can be separated more effectively from unreacted material, and the separation yield can also be increased.
[0042] In the plurality of NaF separation units (10, 10') above, unreacted material may be introduced into each NaF separation unit (10, 10') to mix with washing water, and unreacted material and washing water may be mixed while moving sequentially from the first NaF separation unit (10) to the NaF separation unit (10').
[0043] Water may be used as the washing water, and the washing water may be included in a weight ratio of 1:0.5 to 1:1.5 relative to the NaF content contained in the unreacted material. When the content of the washing water falls within the above range, PCl3 and AN (acetonitrile) contained in the unreacted material can be sufficiently dissolved in the washing water and efficiently separated from NaF.
[0044] The heating can be performed at 70 to 150°C for 4 to 12 hours, and the NaF separation unit (10) may include an evaporator (not shown) inside or outside the NaF separation unit (10) for heating the mixture of the unreacted material and the NaF after reaction.
[0045] The mixed gas containing PCl3 and AN (acetonitrile) generated through the above heating can be supplied to the byproduct recovery unit (20).
[0046] Specifically, the mixed gas containing PCl3 and AN (acetonitrile) generated above can be discharged through a gas outlet (15) located at the top of the NaF separation unit (10) and supplied to a byproduct recovery unit (20). At this time, the temperature of the byproduct recovery unit (20) can be set to 5 to 30°C.
[0047] In the above byproduct recovery unit (20), a mixed gas containing at least one of PCl3 and AN (acetonitrile) supplied can be cooled to condense and recover at least one of PCl3 and AN.
[0048] Subsequently, the condensed PCl3 and AN (acetonitrile) can be transferred to and stored in a storage tank (30) connected to a byproduct recovery unit (20).
[0049] In addition, the mixed gas is separated from the mixture of unreacted material and NaF after reaction in the above NaF separation unit (10), and the remaining NaF slurry can be discharged through the NaF slurry discharge port (14) located at the bottom of the NaF separation unit (10) and supplied to the NaF recovery unit (40).
[0050] Wastewater (washing water) from the NaF slurry supplied to the above NaF recovery unit (40) can be separated and discharged to a wastewater tank (60) connected to the bottom of the NaF recovery unit (40) for storage. After the wastewater is discharged, the remaining NaF slurry can be dried and then filtered through a NaF filter (41) provided inside the NaF recovery unit (40) to recover NaF.
[0051] The above drying can be performed to remove moisture from the NaF slurry. The drying can be performed at a temperature of 100 to 200°C, preferably 120 to 150°C, for 4 to 12 hours to remove sufficient moisture from the NaF slurry.
[0052] Specifically, for the above drying, the NaF recovery unit (40) may include a heating means for evaporating and removing moisture from the NaF slurry, and may include a heating means that heats indirectly by, for example, by circulating hot water. The heating means may be maintained at a temperature of 100 to 200°C.
[0053] The gas generated during the process of drying the above NaF slurry can be supplied to a heat exchanger (50) connected to the above NaF recovery unit (40), and the gas that is not cooled or condensed can be discharged through the heat exchanger (50), and the condensed moisture can be transferred to a wastewater tank (60) connected to the heat exchanger (50). The heat exchanger (50) can be set to a temperature of 10 to 30°C.
[0054] In addition, a method for recovering unreacted NaF according to one embodiment of the present invention can be carried out as follows using the unreacted NaF recovery device described above.
[0055] First, a reaction to generate PF3 gas using PCl3, AN (acetonitrile), and NaF is performed in the PF3 manufacturing unit (1), and then the unreacted mixture of PCl3, AN, and NaF generated in the reaction can be introduced into the NaF separation unit (10).
[0056] Next, the mixture introduced into the NaF separation unit (10) can be heated at 70 to 150°C for 4 to 12 hours to produce a mixed gas containing PCl3 and AN (acetonitrile). The produced mixed gas is supplied to the byproduct recovery unit (20) and cooled and condensed at 5 to 30°C, and the condensed PCl3 and AN (acetonitrile) can be stored in a storage tank (30).
[0057] Next, an excess amount of distilled water can be introduced into the NaF separation unit (10). At this time, the distilled water introduced can be introduced in a weight ratio of 1:0.5 to 1:1.5 relative to the NaF content contained in the unreacted material. The introduced distilled water and the residue are stirred by an impeller (11) equipped with spiral blades (13) so that impurities such as NaCl, HF, and HCl can be dissolved. At this time, the spiral blades (13) of the impeller (11) can maintain an appropriate distance from the inner bottom surface of the NaF separation unit (10) so that unreacted material does not accumulate.
[0058] Next, the stirred mixture can be transferred to a NaF recovery unit (40) and filtered through a NaF filter (41). During the filtering process, undissolved NaF is filtered out by the filter (41), and wastewater containing NaCl, HF, HCl, etc. can be transferred to a wastewater tank (60) and stored.
[0059] Next, the NaF filtered in the NaF recovery unit (40) can be dried at a temperature of 100 to 200°C, more preferably 120 to 150°C for 4 to 12 hours. The steam generated during this process can be cooled and condensed at 10 to 30°C through a heat exchanger (50) and sent to a wastewater tank (60).
[0060] In the above NaF recovery unit (40), a purge process using an inert gas may be additionally performed to further increase the purity of the recovered NaF. The inert gas may be nitrogen or helium, and through this, residual harmful gases can be removed to improve the purity and yield of NaF.
[0061] According to the unreacted NaF recovery method of the present invention as described above, NaF with a purity of 97% or higher can be recovered with a yield of 96% or higher.
[0062] Although embodiments of the invention disclosed above have been illustrated and described, the disclosed invention is not limited to the specific embodiments described above, and various modifications can be made by those skilled in the art to which the disclosed invention belongs without departing from the essence claimed in the claims.
Claims
1. A PF3 manufacturing unit that produces PF3 by reacting a substance containing P with NaF; A NaF separation unit that separates the remaining NaF after producing the above PF3 into insoluble NaF and a mixed gas; and A NaF recovery unit comprising the above-mentioned insoluble NaF that recovers NaF by filtering and drying the insoluble NaF; Device for recovering unreacted NaF.
2. In Paragraph 1, The above NaF separation unit heats the remaining NaF to produce a mixed gas containing at least one of PCl3 and AN, wherein A byproduct recovery unit further comprising condensing the above mixed gas to a predetermined temperature to recover at least one of PCl3 and AN; Device for recovering unreacted NaF.
3. In Paragraph 2, The above NaF separation unit is, Heating the above remaining NaF at 70℃ to 150℃ for 4 to 12 hours, Device for recovering unreacted NaF.
4. In Paragraph 2, The above-mentioned by-product recovery unit is, Condensing the above mixed gas at 5℃~30℃ and storing it in a storage tank, Device for recovering unreacted NaF.
5. In Paragraph 1, The above NaF separation unit is, Separating the insoluble NaF and the Na salt by providing H2O to the insoluble NaF and stirring with an impeller equipped with spiral blades. Device for recovering unreacted NaF.
6. In Paragraph 1, The above device for recovering unreacted NaF is, A wastewater tank for storing the remaining aqueous solution excluding the NaF filtered in the above NaF recovery unit; further comprising Device for recovering unreacted NaF.
7. In Paragraph 5, The above H2O is, Based on the weight percentage of NaF in the above remainder, the ratio of NaF to H2O is 1:0.5 to 1:1.5, Device for recovering unreacted NaF.
8. In Paragraph 6, The remaining aqueous solution excluding the above NaF is, Comprising at least one of NaCl, HF, and HCl, Device for recovering unreacted NaF.
9. In Paragraph 1, The above NaF recovery unit is, After drying the above-mentioned insoluble NaF, purging with an inert gas, Device for recovering unreacted NaF.