Handbook of Silicon Based MEMS Materials and Technologies

23.1. Etch Chemistries

23.1.1. RIE Chemistry

Etchant phase, gas or liquid, has been used as a dividing factor: wet etching in liquids vs. dry etching in gaseous environment, usually in vacuum [1].Wet etching depends on solubility of etch products, and dry etching on their volatility:

Many halides, fluorides, chlorides, bromides and iodides are volatile, as are oxyhalides [2, 3]. Typical etch products include SiF⁴, SiCl⁴, NF³, WF⁶, AlCl³ when silicon ...