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The market demand for high temperature micro-molds is growing rapidly recently. The most important requirements for high temperature micro-molds include high temperature strength and toughness, low thermal expansion coefficient and anti-stick properties. The SiC is one of the best candidate materials used to fabricate micro-molds. Plasma assisted chemical etching is considered to be the most effective method to produce micro-pattern on SiC materials. In this study, RF plasma system was employed to etch SiC material by using CF4 and O2 as the reaction gases. The effects of gas flow ratio of O2/CF4 and etching time on the etched surface morphologies were investigated.
The results show that the element Al from substrate holder involved in plasma etching process, which leads to the formation of Al-F compound film and dominates the etching mechanisms. Film cracking appeared on the etched surface when the gas flow ratio of O2/CF4 is over 1. If the ratio of O2/CF4 is less than 1, the undercut phenomena and film flaking were observed on the etched surface. The best surface morphology and surface roughness can be obtained when the gas flow ratio of O2/CF4 equals to 1. The depth of etched holes increases with increasing the etching time. The etching depth of 600 nm can be achieved after a 3-hour plasma etching treatment at RF power of 500 W.
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