Preparation Of High Purity Nitrous Oxide

With the rapid development of semiconductor integrated circuit industry in China, the demand for the variety of high purity gases is increasing. As an electronic gas, the high purity nitrous oxide (NzO) is mainly used in the dielectric film technology of the development and production of semiconductor optoelectronic components, and it is an irreplaceable key electronic gas that directly affects the quality of photoelectric device. High purity nitrous oxide (N2O) as the key gas source material and the SiO2thin film deposition by PECVD technique, the masking film, passive film, anti-reflectance coating formation, high purity nitrous oxide (N2O) are the key essential raw materials. This paper mainly uses the pharmaceutical grade nitrous oxide (N2O) as raw material, through a combined method of high-pressure adsorption at normal temperature, and low temperature condensation and evacuation to deeply remove various impurities in nitrous oxide (N2O), developing high purity of99.999%nitrous oxide (N2O) product.A multi-unit integrated deep purification device was set up. The studies of analysis detection method for the harmful impurities in high purity nitrous oxide, and the effect of modified adsorbent on the impurity adsorption performance of nitrous oxide impurities were carried out. Conclusions are drawn as follows:1. The various harmful impurities in nitrous oxide were deeply removed through a combined technology of multi-unit integrated deep purification and low-temperature condensation and evacuation. The modified13X molecular sieve, modified5A molecular sieve and modified3A molecular sieve were used as adsorbents. The various harmful impurities contents in the purified nitrous oxide met the requirements of technical indicators, with a purity of99.999%.2. A set of analysis methods of detecting various impurities in nitrous oxide (N2O) was established according to the5N level high purity nitrous oxide (N2O).3. The experimental data showed that the times of low temperature condensation and evacuation had great influence on the separation of impurity O2. N2in nitrous oxide (N2O), and the optimal operation number is4.4. The experimental data showed that the working pressure of nitrous oxide purification system had great influence on the purification of nitrous oxide impurities; when the working pressure of purification system was between2.5-3.0MPa, the performance of adsorbent for deeply removing the impurity H2O, CO2, NOx and THC was greatly improved, reducing the impurity H2O and CO2content to less than1.0ppm and the NOx, THC content to less than0.2ppm, and meeting the requirements of technical indicators.5. The influence of gas flow rate on the adsorption performance was investigated. The result showed that when the nitrous oxide velocity was lower than4.0L/h, the deep removing effect of the adsorbent on the impurities could be achieved such as H2O, CO2, NOx and THC, etc. in nitrous oxide with the impurity content meeting the requirements of technical indicators for99.999%high purity nitrogen oxide. However, when the gas flow rate was too low, the nitrous oxide production efficiency would be affected, therefore, the optimal production rate of high purity nitrous oxide production was4.0L/h.