Experimental Research Of Fluorocarbon Films Prepared By ICP-CVD

Fluorocarbon thin films(FC) exhibit unique properties such as low-k dielectric constant(2.0±1), high thermal stability, low coefficient of friction, hydrophobicity, low index of refraction, and so on, which causes abroad attention in industry. With the decreasing in integrated circuits feature size and increasing ratio of diameter-to-length, production efficiency of new electric-optics materials has been restricted by these novel bugs, especially in optical films, high request put forward for the surface structure. Interfacial atomic level roughness of material plays a key role in the type and distributing of these bugs. In addition, although great effort has been paid in the preparation methods, reactive dynamics, structure and character analysis of the FC films, the research of the optical emission spectra diagnose for the plasma and the mechanism of the depositing process is less. Therefore making the FC films with atomic level smooth surface and studying the mechanism of the deposition process have important meaning for the manufacturing of this material.In this paper, inductively coupled plasma was used to prepare the films, for this method has some advantages, for example, low pressure discharge, high density, large uniformity discharge area, and the precursors were CH2F2, C2F6, C3F8 and C4F8. The effects of varying the pressure, r.f. power, cw/pulsed discharge mode, and the distance of the substrate from the coil on surface roughness were mainly investigated. The films were characterized by Fourier transform infrared spectrophotometer(FTIR) and X-ray photoelectron spectroscopy(XPS). Water contact angles were measured by sessile drop method. Surface Profiler was used to measure the film thickness. Experimental results show that the mostly films deposited by C2F6 and C3F8 have the Polytetrafluoroethylene structure, atomic level smooth morphology and high(>100o) hydrophobicity, but with low deposition rate. These cw and pulsed deposition systems were characterized in-situ by means of optical emission spectroscopy, Emission intensities of various species as a function of plasma parameters were measured. Base on these results, the"gas phase-surface cooperate growth model limited by temporal and spatial differences"of the deposition mechanism of FC films was suggested. And also the proper position satisfied manufacturing arts and crafts was deduced for this experiment device.