KR20050023949A - Purification of nitrogen trifluoride gas - Google Patents

Purification of nitrogen trifluoride gas Download PDF

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KR20050023949A
KR20050023949A KR1020030061727A KR20030061727A KR20050023949A KR 20050023949 A KR20050023949 A KR 20050023949A KR 1020030061727 A KR1020030061727 A KR 1020030061727A KR 20030061727 A KR20030061727 A KR 20030061727A KR 20050023949 A KR20050023949 A KR 20050023949A
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nitrogen trifluoride
reducing agent
oxidative impurities
impurities
gas
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KR100553987B1 (en
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천경우
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주식회사 소디프신소재
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    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B21/00—Nitrogen; Compounds thereof
    • C01B21/082—Compounds containing nitrogen and non-metals and optionally metals
    • C01B21/083—Compounds containing nitrogen and non-metals and optionally metals containing one or more halogen atoms
    • C01B21/0832—Binary compounds of nitrogen with halogens
    • C01B21/0835—Nitrogen trifluoride
    • C01B21/0837—Purification
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B2210/00—Purification or separation of specific gases
    • C01B2210/0001—Separation or purification processing
    • C01B2210/0003—Chemical processing
    • C01B2210/0006—Chemical processing by reduction
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B2210/00—Purification or separation of specific gases
    • C01B2210/0043—Impurity removed
    • C01B2210/0051—Carbon dioxide
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B2210/00—Purification or separation of specific gases
    • C01B2210/0043—Impurity removed
    • C01B2210/0075—Nitrogen oxides
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B2210/00—Purification or separation of specific gases
    • C01B2210/0043—Impurity removed
    • C01B2210/0098—Other impurities
    • 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

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  • Organic Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Treating Waste Gases (AREA)
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Abstract

PURPOSE: To economically prepare high purity nitrogen trifluoride in which oxidative impurities such as OF2 and F2 exist in extremely small quantities, and which does not contain CO2, NO and NO2 at all by treating nitrogen trifluoride with an aqueous reducing agent solution in a pH range of 8 to 12, thereby effectively removing oxidative impurities. CONSTITUTION: A purification method of nitrogen trifluoride(NF3) gas is characterized in that nitrogen trifluoride gas containing oxidative impurities is treated with an aqueous reducing agent solution in a pH range of 8 to 12, wherein the aqueous reducing agent solution is an aqueous solution containing 0.1 to 20 wt.% of a reducing agent elected from Na2S2O3, Na2SO3, HI, K2S2O3, K2SO3 and a mixture thereof, wherein purified nitrogen trifluoride contains 0.05 ppm or less of oxidative impurities, wherein the oxidative impurities are OF2, F2, CO2, NO, NO2 or a mixture thereof, and wherein nitrogen trifluoride containing oxidative impurities is derived from a process of reacting the prepared fluorine with ammonia or ammonium salts such as ammonium fluorides after preparing fluorine(F2) by electrolyzing hydrofluoric acid(HF) or a process of directly electrolyzing fluorides of ammonia(NH3).

Description

삼불화질소 가스의 정제방법{PURIFICATION OF NITROGEN TRIFLUORIDE GAS}Purification method of nitrogen trifluoride gas {PURIFICATION OF NITROGEN TRIFLUORIDE GAS}

본 발명은 삼불화질소(NF3) 가스를 정제하는 방법에 관한 것이다. 본 발명에 따르면, 공업적으로 값싸고 산화성 불순물이 거의 없는 고순도 삼불화질소(NF3)를 제공할 수 있다.The present invention relates to a method for purifying nitrogen trifluoride (NF 3 ) gas. According to the present invention, it is possible to provide high purity nitrogen trifluoride (NF 3 ) which is industrially inexpensive and almost free of oxidative impurities.

삼불화질소(NF3)는 CVD 장치의 클리닝제 및 반도체의 에칭제로서 공업적으로 널리 사용되고 있다. 최근 클리닝제 및 에칭제의 용도에 사용되는 삼불화질소(NF3)의 순도는 점점 고순도의 것이 요구되고 있다.Nitrogen trifluoride (NF 3 ) is widely used industrially as a cleaning agent for CVD apparatuses and an etching agent for semiconductors. In recent years, the purity of nitrogen trifluoride (NF 3 ) used in the use of cleaning agents and etching agents is increasingly required.

삼불화질소(NF3)의 공업적인 생산방법은 불산(HF)을 전기분해하여 불소(F2)를 제조하고 이 불소(F2)에 암모니아(NH3) 또는 불화암모늄등의 암모늄염을 반응시켜서 삼불화질소(NF3)를 얻는 방법 또는 암모니아의 불화물을 직접 전기분해하여 삼불화질소를 얻는 방법이 일반적이다.The industrial production method of nitrogen trifluoride (NF 3 ) is to produce fluorine (F 2 ) by electrolyzing hydrofluoric acid (HF) and reacting the fluorine (F 2 ) with an ammonium salt such as ammonia (NH 3 ) or ammonium fluoride It is common to obtain nitrogen trifluoride (NF 3 ) or to obtain nitrogen trifluoride by directly electrolyzing fluoride of ammonia.

그렇지만, 이들 방법으로 제조된 삼불화질소(NF3)에는 통상 각종 부반응에 의해 생성되는 OF2, F2 등의 산화성 불순물이 존재하여 고순도를 요구하는 삼불화질소(NF3)로서는 불충분하다는 것이 당업계에서 인식되어 왔다. 특히, 용융염 전기분해법에 의해 제조된 삼불화질소의 경우는 수백 ppm 정도의 산화성 불순물이 함유되는 것으로 나타난다.However, nitrogen trifluoride (NF 3 ) prepared by these methods is usually insufficient as nitrogen trifluoride (NF 3 ) which requires high purity because oxidative impurities such as OF 2 and F 2 produced by various side reactions are present. It has been recognized in the industry. In particular, nitrogen trifluoride produced by molten salt electrolysis appears to contain several hundred ppm of oxidative impurities.

이 산화성 불순물은 삼불화질소 가스 정제 과정에서 분해되어 발열하기 쉬우므로 폭발 위험성이 크고 다른 불순물인 CO2나 N2O 등의 흡착능이 매우 저하될 수 있으며, 삼불화질소를 이용한 반도체나 소자의 드라이 에칭시나 기판 클리닝시 제품에 악영향을 미칠 수 있으므로, 이를 감소시키는 방법으로서 Na2S2O3, Na2SO3, HI, K2S2O3, K2SO3 등의 환원제 수용액을 사용하여 제거시키는 방법이 제안되었지만 그 최적 조건이 정립되지 않아 제거가 불충분하여 왔다 (미국 특허 제 4,980,144 호, 한국 특허공개 제 2003-21662 호 참조).Since this oxidative impurity is easily decomposed and generated during nitrogen trifluoride gas refining process, there is a high risk of explosion and the adsorption capacity of other impurities such as CO 2 and N 2 O may be very deteriorated. Since it may adversely affect the product during etching or cleaning the substrate, as a method of reducing this by using a reducing agent aqueous solution such as Na 2 S 2 O 3 , Na 2 SO 3 , HI, K 2 S 2 O 3 , K 2 SO 3 A removal method has been proposed but its removal has been insufficient because its optimum conditions have not been established (see US Patent No. 4,980,144 and Korean Patent Publication No. 2003-21662).

따라서, 본 발명자들은 상기 환원제 수용액의 처리시 최적 조건을 확립하기 위해 연구한 결과 그 사용에 맞는 최적 pH 범위가 있음을 발견하여 본 발명을 완성하게 되었다. Accordingly, the present inventors have completed the present invention by finding that there is an optimum pH range suitable for use as a result of studying to establish optimum conditions in the treatment of the reducing agent aqueous solution.

상기 기술적 과제를 이루기 위하여, 본 발명에서는, 산화성 불순물을 함유하는 조 삼불화질소(NF3) 가스를 pH 8 내지 12 범위의 환원제 수용액으로 처리함을 포함하는 삼불화질소(NF3) 가스의 정제 방법을 제공한다.In order to achieve the above technical problem, in the present invention, purification of nitrogen trifluoride (NF 3) gas containing the crude nitrogen trifluoride (NF 3) gas containing an oxidizing impurities also treated with a reducing agent aqueous solution of pH 8 to 12 range Provide a method.

본 발명의 방법에 있어서 특징인 적정 pH의 환원제 용액에 의한 처리공정은, 특히 불산(HF)을 전기분해하여 불소(F2)를 제조하고 이 불소(F2)에 암모니아(NH3 ) 또는 불화암모늄등의 암모늄염을 반응시켜서 삼불화질소(NF3)를 얻는 방법, 또는 암모니아(NH3)의 불화물을 직접 전기분해하여 삼불화질소(NF3)를 얻는 방법 등에 정제공정으로서 응용할 수 있다.The treatment process with a reducing agent solution of a suitable pH characterized by the method of the present invention, in particular, hydrolyzes hydrofluoric acid (HF) to produce fluorine (F 2 ), and ammonia (NH 3 ) or fluoride is added to the fluorine (F 2 ). by reaction of an ammonium salt such as ammonium can be applied as purification step nitrogen trifluoride how to get (NF 3), or a method of obtaining the nitrogen trifluoride (NF 3) three fluorine by direct electrolysis of ammonia (NH 3) or the like.

본 발명의 방법에 따른, 산화성 불순물을 포함한 삼불화질소(NF3)가스와 환원제 수용액과의 접촉방법은 통상, 충전탑, 다층탑, 스프레이탑 등의 기액접촉장치가 사용되지만, 이들에 국한되는 것은 아니다.According to the method of the present invention, a method of contacting nitrogen trifluoride (NF 3 ) gas containing an oxidative impurity with a reducing agent aqueous solution is usually used, but a gas-liquid contact device such as a packed column, a multilayer tower, a spray tower, etc. is used, but is not limited thereto. no.

본 발명의 방법에 있어서 환원제 수용액에 사용되는 환원제로는 Na2S2O3, Na2SO3, HI, K2S2O3, K2SO3 등을 사용할 수 있으며, 그의 농도는 약 0.1 내지 20 중량%가 적합하다. 환원제 수용액의 농도가 0.1% 보다 낮으면 산화성 불순물의 제거속도가 느리고 수용액 사용량이 많아져서 폐수량이 과다해지며, 농도가 20% 이상이면 용액의 점도가 높아져 취급이 곤란하고 경제성이 없다.In the method of the present invention, a reducing agent used in the reducing agent solution may be Na 2 S 2 O 3 , Na 2 SO 3 , HI, K 2 S 2 O 3 , K 2 SO 3, etc., and the concentration thereof is about 0.1. To 20% by weight is suitable. When the concentration of the reducing agent solution is less than 0.1%, the removal rate of oxidative impurities is slow and the amount of the aqueous solution is used is excessive, and the waste water amount is excessive. When the concentration is 20% or more, the viscosity of the solution is difficult to handle and economical.

본 발명에 따른 환원제 용액의 pH의 조정은 NaOH, KOH 등의 알칼리를 이용하여 수행할 수 있고, 특히 KOH가 바람직하지만, 그에 한정되는 것은 아니다. 본 발명의 방법에 있어서 환원제 수용액의 pH가 8이하이면 산화성 불순물을 제거한 삼불화질소(NF3)가스 안에 CO2, NO, NO2 등의 산성 가스가 혼입되어, 삼불화질소(NF 3) 제품의 순도 저하를 초래하게 되므로 효과적이지 못하고, 환원제 수용액 pH가 12이상이면 알칼리 사용량이 늘어나므로 경제적이지 못하다.Adjustment of the pH of the reducing agent solution according to the present invention can be carried out using an alkali such as NaOH, KOH, in particular KOH is preferred, but is not limited thereto. In the method of the present invention, when the pH of the reducing agent solution is 8 or less, acidic gases such as CO 2 , NO, and NO 2 are mixed into the nitrogen trifluoride (NF 3 ) gas from which oxidative impurities are removed, thereby producing a nitrogen trifluoride (NF 3 ) product. It is not effective because it leads to a decrease in the purity of, and if the pH of the reducing agent aqueous solution is 12 or more, the amount of alkali used is not economical.

삼불화질소는 통상의 방법으로 제조시 수십 내지 수천 ppm의 산화성 불순물을 포함하고 있는데, 본 발명에 따르면, OF2, F2 등의 산화성 불순물이 0.05 ppm 이하의 극미량인 고순도 삼불화질소(NF3)를 제공할 수 있어, 이를 다양한 분야에서 클리닝제 또는 에칭제로서 유용하게 이용할 수 있다.Nitrogen trifluoride contains tens to thousands of ppm of oxidative impurities when manufactured by a conventional method. According to the present invention, high purity nitrogen trifluoride (NF 3) having an extremely small amount of oxidative impurities such as OF 2 and F 2 is 0.05 ppm or less. ), Which can be usefully used as a cleaning agent or an etchant in various fields.

하기 실시예로서 본 발명을 설명하나, 본 발명이 이로써 국한되는 것은 아니다.The invention is illustrated by the following examples, but the invention is not so limited.

실시예 1Example 1

탑경 50mm, 높이 500mm의 충전탑을 사용하여, 충전탑 아래로부터는 질소 70%, OF2 180ppm, F2 40ppm의 산화성 불순물 및 CO2 1ppm을 포함한 삼불화질소(NF 3)가스를 매시간 50리터의 유량으로 공급하면서, 충전탑에 K2S2O3 5.0%, pH 9.5로 KOH로 pH 조정된 수용액을 매시간 200리터의 유량으로 순환시켜 이를 삼불화질소 가스와 접촉시켰다. 탑상부로부터 얻어지는, 질소로 30%로 희석된 삼불화질소(NF3)가스 안에는 OF2, F2의 산화성 불순물 및 CO2, NO, NO2등의 산성가스는 검지되지 않았다.Using a 50mm tower and a 500mm high tower, nitrogen trifluoride (NF 3 ) gas containing 70% nitrogen, OF 2 180ppm, F 2 40ppm oxidative impurities and 1ppm CO 2 was charged from below. While feeding at a flow rate, the packed column was contacted with nitrogen trifluoride gas by circulating an aqueous solution adjusted to KOH to 5.0% K 2 S 2 O 3 , pH 9.5 at a flow rate of 200 liters every hour. In the nitrogen trifluoride (NF 3 ) gas diluted with nitrogen at 30% obtained from the top of the column, oxidative impurities of OF 2 and F 2 and acidic gases such as CO 2 , NO and NO 2 were not detected.

실시예 2Example 2

상기 실시예 1과 동일하되, 환원제 수용액으로서 Na2S2O3 3.0%, pH 10으로 NaOH로 pH 조정된 수용액을 사용하여 삼불화질소를 정제하였으며, 탑상부로부터 얻어지는, 질소로 30%로 희석된 삼불화질소(NF3)가스 안에는 OF2, F2의 산화성 불순물 및 CO2, NO, NO2등의 산성가스는 인지되지 않았다.Nitrogen trifluoride was purified in the same manner as in Example 1, but using an aqueous solution adjusted to pH NaOH with Na 2 S 2 O 3 3.0% and pH 10 as an aqueous reducing agent, and diluted with 30% nitrogen obtained from the top of the column. The oxidized impurities of OF 2 and F 2 and acidic gases such as CO 2 , NO and NO 2 were not recognized in the nitrogen trifluoride (NF 3 ) gas.

비교예 1Comparative Example 1

상기 실시예 1과 동일하되, 환원제 수용액으로서 K2S2O3 5.0%, pH 7로 KOH로 pH 조정된 수용액을 사용하여 삼불화질소를 정제하였으며, 탑상부로부터 얻어지는, 질소로 30%로 희석된 삼불화질소(NF3)가스 안에는 OF2, F2의 산화성 불순물은 인지되지 않았고 CO2가 0.5 ppm 인지되었다.Nitrogen trifluoride was purified in the same manner as in Example 1 except using 5.0% K 2 S 2 O 3 as a reducing agent aqueous solution and pH adjusted to KOH to pH 7, and diluted with 30% nitrogen obtained from the top of the column. The oxidized impurities of OF 2 and F 2 were not recognized in the nitrogen trifluoride (NF 3 ) gas and 0.5 ppm of CO 2 was recognized.

본 발명에 따르면, 삼불화질소를 pH 8 내지 12 범위의 환원제 수용액으로 처리하여 산화성 불순물을 효과적으로 제거함으로써 OF2, F2 등의 산화성 불순물이 극미량으로 존재하고 CO2, NO, NO2 등은 전혀 없는 고순도의 삼불화질소를 경제적으로 제조할 수 있다.According to the present invention, by treating nitrogen trifluoride with a reducing agent solution in a pH range of 8 to 12 to effectively remove oxidative impurities, oxidative impurities such as OF 2 and F 2 are present in a very small amount, and CO 2 , NO, NO 2, etc. are completely absent. High purity nitrogen trifluoride free can be produced economically.

Claims (5)

산화성 불순물을 함유하는 삼불화질소 가스를 pH 8 내지 12 범위의 환원제 수용액으로 처리함을 특징으로 하는, 삼불화질소(NF3) 가스의 정제 방법.A process for purifying nitrogen trifluoride (NF 3 ) gas, characterized by treating a nitrogen trifluoride gas containing oxidative impurities with an aqueous reducing agent solution in a pH range of 8 to 12. 제 1 항에 있어서,The method of claim 1, 상기 환원제 수용액이 Na2S2O3, Na2SO3, HI, K2 S2O3, K2SO3 및 이의 혼합물 중에서 선택된 환원제의 0.1 내지 20 중량% 수용액임을 특징으로 하는 방법.The reducing agent aqueous solution is characterized in that the Na 2 S 2 O 3 , Na 2 SO 3 , HI, K 2 S 2 O 3 , K 2 SO 3 And 0.1 to 20% by weight aqueous solution of the reducing agent selected from mixtures thereof. 제 1 항에 있어서,The method of claim 1, 정제된 삼불화질소가, 산화성 불순물을 0.05 ppm 이하의 양으로 함유함을 특징으로 하는 방법. The purified nitrogen trifluoride contains oxidative impurities in an amount of 0.05 ppm or less. 제 3 항에 있어서,The method of claim 3, wherein 산화성 불순물이 OF2, F2 , CO2, NO, NO2 또는 이들의 혼합물임을 특징으로 하는 방법.Oxidizing impurities are OF 2 , F 2 , CO 2 , NO, NO 2 or mixtures thereof. 제 1 항에 있어서,The method of claim 1, 산화성 불순물을 함유하는 삼불화질소가, 불산(HF)을 전기분해하여 불소(F2)를 제조하고 이 불소(F2)에 암모니아(NH3) 또는 불화암모늄등의 암모늄염을 반응시키는 공정 또는 암모니아(NH3)의 불화물을 직접 전기분해하는 공정으로부터 유래된 것임을 특징으로 하는 방법.Nitrogen trifluoride containing oxidative impurities produces fluorine (F 2 ) by electrolyzing hydrofluoric acid (HF) and reacting the fluorine (F 2 ) with an ammonium salt such as ammonia (NH 3 ) or ammonium fluoride or ammonia And (NH 3 ) derived from the process of directly electrolyzing the fluoride.
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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112742158A (en) * 2020-12-30 2021-05-04 中船重工（邯郸）派瑞特种气体有限公司 Hydrogen fluoride waste gas treatment system and method in nitrogen trifluoride electrolysis preparation process
CN116254547A (en) * 2022-12-30 2023-06-13 福建德尔科技股份有限公司 Preparation method of nitrogen trifluoride

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112742158A (en) * 2020-12-30 2021-05-04 中船重工（邯郸）派瑞特种气体有限公司 Hydrogen fluoride waste gas treatment system and method in nitrogen trifluoride electrolysis preparation process
CN116254547A (en) * 2022-12-30 2023-06-13 福建德尔科技股份有限公司 Preparation method of nitrogen trifluoride
CN116254547B (en) * 2022-12-30 2023-09-08 福建德尔科技股份有限公司 Preparation method of nitrogen trifluoride

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