Purification Of High Purity Boron Trichloride

High purity boron trichloride is used in the film forming process of CVD and dry plasma etching process whose technical requirements are very high and whose impact on the rate of circuit products is considerable in IC manufacturing techniques. It plays a very critical role in the quality of IC products and it can not be replaced by other electronic gases. Its impurity content and purity will directly affect the quality, performance, technical specifications and finished product rate of IC and electronic components. In order to ensure the quality and reliability of military IC products, a high demand is put forward for supporting gasses of raw materials. It is required that the purity of three boron chloride is more than 99.999%(5N). While the boron trichloride whose purity is more than 99.999%(5N)can not be produced domestically and the products in this grade are totally imported from several large companies from the United States, Britain, Japan. This paper takes the crude three boron chloride as the raw material to remove the impurities by adopting the combination approach of high pressure absorption at room temperature and evacuation in low temperature cooling. Finally, the boron trichloride whose purity is more than 99.999%(5N)will be produced. The deep purification process system with a set of multiple units being combined is created to carry out research on the testing methods for harmful impurities gases of boron trichloride with high purity. After exploring the effect of the modified adsorbent on the adsorption properties of the material, the following results are obtained:1. A lot of harmful impurities in boron trichloride are removed deeply by using KY-05 molecular sieve which is produced by the researcher and choosing deep purification of multiple unit combination and the combination of evacuation in low temperature cooling. After purity, harmful impurities content in three boron chloride is in line with the corresponding requirements and the purity is up to 99.999%.2. According to inspection requirements for impurities in 5N boron trichloride, a set of inspection method for all impurities of boron trichloride is constructed.3. In the discussion that supercritical gasification is used to remove the O?22 N boron trichloride, the experimental data shows that the time of condensation and evacuation have significant impact on the removal of oxygen and nitrogen impurities and the optimum time to obtain the highly-purified boron trichloride is 4.4. The effect of gas flow rate on the adsorption performance is also discussed. The results show that when the flow rate of boron trichloride is less than 3L/min, the adsorbent can effectively remove the CO?CO2?THCand other impurities in boron trichloride. T he impurity concentration is in line with the requirements of 99.999% boron trichloride, but the gas flow rate which is not high will affect the production capacity. Therefore, the best production flow rate for producing high purity boron trichloride is 3L/min.5. The effect of adsorption pressure of molecular sieve at room temperature on removal of impurities in BCl3 is discussed. It shows that because the pressure of the system is enhanced, the corresponding concentration of impurities in BCl3 is decreased significantly.6. The research on the stability of BCl3 is carried out and the regenerative replacement gases of the adsorption system are compared and screened.