Purity control in fluorine-nitrogen (F₂/N₂) gas production centers around five critical stages: raw material control, impurity removal, precise gas blending, system protection, and real-time monitoring. Strict control of trace impurities such as HF, moisture, oxygen, and carbon-containing compounds is essential to ensure blending accuracy and process stability.
Raw Material Control — The Foundation of Gas Purity
The process should use 5N-grade high-purity nitrogen, with strict control of moisture and oxygen impurities. For electrolytic production of crude fluorine, electronic-grade anhydrous hydrogen fluoride (HF) should be used as the feedstock to prevent impurities from entering at the source. At the same time, the electrolysis temperature and slightly positive-pressure operating conditions should be carefully controlled to prevent air ingress and impurities caused by feedstock volatilization, while minimizing the formation of dust and other harmful by-products.
Core Impurity-Control Step — Deep Purification of Crude Fluorine
Most of the HF can first be removed through cryogenic condensation. A fluorine-compatible adsorbent can then be used for deep removal of trace HF and moisture, while low-temperature distillation can be employed to remove light impurities such as oxygen. In addition, multi-stage precision filtration is used to remove fluoride-containing particulates. Through these combined purification steps, various trace impurities can be controlled at the ppm level or even lower.
Gas Blending Stage
High-precision mass flow controllers (MFCs) or partial-pressure-based blending methods can be used to achieve accurate gas ratios. A static mixer ensures uniform mixing of the gases, while stable temperature and pressure conditions help prevent concentration fluctuations. The entire system should use fluorine-resistant materials such as Monel and PFA. Before commissioning, the system should undergo thorough degreasing, dehydration, and passivation treatment to prevent leakage, adsorption, and secondary contamination throughout the process.
Online Raman Analysis by JINSP
The entire process can leverage JINSP online Raman analyzers to establish a high-precision, end-to-end process quality-control system, replacing conventional single-parameter measurement approaches. The analyzer is designed to operate under highly corrosive fluorine-containing gas conditions and can simultaneously monitor multiple components at second-level response speeds, including F₂ concentration, HF, O₂, and carbon-containing compounds. Detection can achieve ppm-level sensitivity, with a repeatability error of < ±1% and excellent linearity.
The analyzer can be integrated with a fluorine-resistant, passivated sampling system, eliminating the need for manual sampling. It enables real-time monitoring of gas conditions throughout the electrolysis, purification, and blending stages, allowing impurity fluctuations and blending deviations to be detected promptly and process parameters to be adjusted automatically.
For calibration and reference verification, the system can also be combined with offline titration and chromatographic analysis. This helps address the limitations of conventional online analyzers, such as limited component coverage and insufficient resistance to interference.
By establishing a closed-loop quality-control system across the entire process, the solution can effectively minimize problems caused by sampling adsorption and contamination during sample transfer.
This helps ensure precise fluorine-nitrogen gas concentrations and stable, controllable impurity levels, meeting the stringent purity requirements of advanced applications such as semiconductor etching and precision chamber cleaning.
Post time: Sep-18-2026