ANALYSIS OF FLUOROCARBON FILM DEPOSITED BY HIGHLY SELECTIVE OXIDE ETCHING

The influence of fluorocarbon film composition on oxide etching select ivity have been studied in a CHF3/CO mixture-gas plasma, using a magne tron-enhanced reactive ion etching system. The Fluorocarbon-film depos ition rate dependence on CO concentration was measured. The Sputtering rate and carbon concentration of fluorocarbon films, which were depos ited under various CO concentrations, were investigated. With CO addit ion, the carbon concentration in the fluorocarbon film increases, and the sputtering rate of the deposited film is reduced. High carbon conc entration in a deposited polymer can enhance the selectivity of etchin g by protecting the Si surface from ion bombardment. In addition, an a dequate CO mixing can yield a high selectivity of polymer deposition o n a Si surface as compared to an oxide surface, which, iii turn, achie ves a high selectivity in oxide etching on Si.