Environment friendly MEMS fabrication: Proposal of new D-RIE process gases for reduction of green house effect

Environmental emission volume of green house gases such as SF₆ and C₄F₈, consumed for Si deep etching process in MEMS fabrication, are increasing followed by the MEMS market growth. To reduce the emitted green house gases, alternative C₃F₆ and IF₅ were investigated to be applied for MEMS etching process instead of conventional Bosch process gases. The C₃F₆ and IF₅ gases have very small global warming potential, so that they were useful to reduce over 95% of the green house gases maintaining the good etching performance on both etching rate and etching profile. The reduction of warming gas emission by the new gases is estimated that approximately 43 trees might be conserved during one etching process of a wafer to 300 mum. In addition to this merit, IF₅ is found to be applied for anisotropic trench etching without Bosch process.