| Reactive ion etching(RIE) characteristics of TiN film coated on a cemented carbide was studied with CF₄/O₂ mixture. The etching rates of the film were measured as a function of gas mixture ratio, RF power, substrate temperature, and pressure. The etching rate was increased with the increase of O₂ gas concentration and reached a maximum value at about 20% of O₂ and above which the rate was decreased. The etching rates were increased with the RF power, the pressure, and the substrate temperature. The Arrhenius plot of the etch rates versus the reverse substrate temperature shows activation energies of 5.0 ㎉/㏖ and 4.2 ㎉/㏖ for CF₄/20% O₂ and CF₄, respectively. The chemical composition of the etched surface was analyzed by X-ray photoelectron spectroscopy(XPS). Fluorine atoms were detected in the base material because it diffused into the substrate in CF₄/20% O₂plasma. Atomic force micro-roughness measurement showed a smooth surface when it was etched with CF₄, but the roughness was increased by adding 20% O₂. The cuttability was not degraded by the re-deposition of TiN film on the cemented carbide after the etching process. |
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