Study on fabrication of the diamond film gear in micro-system

Although the diamond film is one of the most potential micromachining structures functional materials, it is rather difficult to molded because of its extremely high hardness and chemical stability. In this article, we applied a method for micro-gear structure producing based on Reactive Ion Etching (RIE) of diamond film and consequently produced diamond film gear which has a thickness of 5¿m and a modulus of 0.003. The result of our experiments applied that the diamond film pattern that has smooth surface, clear contours and vertical sidewall can be produced by using NiTi alloy film and the photoresist etching together as the mask for diamond film. Etching rate and the flatness of etching side can be affected by the process parameters of etching of O₂ or O₂/ Ar mixed gas to diamond films patterning such as RF power, system pressure, flow and the proportion of mix gas. When there are pressure of 12 pa and flow of 50sccm steadily, RF power and etching rate varies linearly. While RF power is too high, higher than 135 w, diamond film turn black for the deposited on its surface generated by the mask. For a given instant process condition, the etching rate of the diamond film isn't strongly depends on the O₂ concentration in the gas mixture.