Purification of nitrogen trifluoride

一种浓度、杂质的技术,应用在获得高纯度三氟化氮领域,能够解决低效率、高经济成本等问题

Inactive Publication Date: 2008-05-28
HONEYWELL INT INC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0011] All of these methods have a serious disadvantage: that is, the adsorbent adsorbs the target product (i.e., NF 3 ), without adsorbing contaminating NF 3 relatively small amount of impurities
The inefficiencies associated with these purification methods are not related to obtaining purified NF 3 The high economic cost of the product is associated with

Method used

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  • Purification of nitrogen trifluoride

Examples

Experimental program
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Effect test

preparation example Construction

[0019] NF 3 The preparation method generally prepares various levels of CF 4 impurity crude NF 3 flow. crude NF 3 Typically contains from about 100 ppm to about 2% by volume of CF 4 , according to the present invention, this crude product is suitable for purification, although a wide range of concentrations of CF can also be purified by the present invention 4 , eg 4ppm to 5% by volume or higher. It is contemplated that crude products containing any concentration of impurities can be processed in accordance with the claimed invention, provided that appropriate bed sizes and flow rates are utilized.

[0020] The crude product of the present invention can be in any phase including gas, liquid, supercritical phase or some combination of these phases. NF at different temperatures 3 The vapor pressure is well known and will determine the NF being treated 3 phase. For example, at atmospheric pressure (760mm Hg), NF 3 The boiling point is -129.1°C. Therefore, according to ...

Embodiment 1

[0039] Before use, place 10 g of CARBOSPHERE with a particle size of 60 / 80 in a vacuum oven at 100°C Carbon molecular sieve drying. This material was loaded into a 300 mL stainless steel cylinder with NF 3 has about 1995ppmv CF 4 The crude product of impurities was pressurized to about 23 psia. After about 2.3 hours, the gas in the cylinder was analyzed by gas chromatography and found to contain less than 1 ppmv of CF 4 . This example demonstrates that CARBOSPHERE  Carbon molecular sieve to CF 4 Compare NF 3 The adsorption is more selective. This example also demonstrates that CARBOSPHERE  Molecular sieves can be used to effectively reduce NF 3 CF in gas composition 4 Impurities.

Embodiment 2

[0041] According to the method of Example 1, the difference is that 9.8 grams of CARBOSPHERE  Molecular sieves are loaded into the cylinder, and will contain about 2.3% by volume CF at a pressure of about 25 psia 4 NF 3 The crude product was loaded into a cylinder. After about 2.1 hours, the gas in the cylinder was analyzed by gas chromatography and found to contain 0.12% by volume CF 4 .

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Abstract

A process and system for adsorption purification of NF3 wherein a crude product containing NF3 and impurities such as CF4 is brought into contact with a polyacrylonitrile-based carbon molecular sieve so that at least a portion of one or more impurities are adsorbed by the sieve without a significant adsorption of the NF3.

Description

field of invention [0001] The present invention relates to obtaining high-purity nitrogen trifluoride (NF 3 )Methods. In particular, the present invention relates to the ability to prepare 4 ) of NF 3 NF 3 Purification method. Background of the invention [0002] Nitrogen trifluoride is widely used in the preparation of semiconductor materials in high-energy lasers and chemical vapor deposition methods. Certain fabrication processes, such as etching semiconductor materials, require very pure NF 3 source, because even small amounts of impurities especially CF 4 Can lead to the formation of solid residues of carbon or silicon carbide, which can cause problems during semiconductor etch operations. In order to be applicable to most electronic device fabrication processes, NF 3 The purity must be 99.9% to 99.999%. [0003] Nitrogen trifluoride can be produced by several methods, including electrolysis of molten ammonium bifluoride, reaction of fluorine gas with ammonium ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B21/083
CPCC01B21/0837C01B21/04C01B21/083
Inventor R·R·辛D·F·奥尔洛夫斯基M·H·卢利M·R·保内桑
Owner HONEYWELL INT INC
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