Etching
Basic principles of dry etching
1. Gas reaction**: In dry etching, gases such as fluoride and chloride are usually used as etchants. These gases react with the material to be etched in a plasma state to form volatile byproducts.
2. Plasma generation**: The gas is converted into plasma by means of radio frequency (RF) excitation or microwave excitation. In the plasma, the gas molecules are ionized to produce free radicals and ions, which can effectively react with the material.
3. Selective etching**: Dry etching can achieve high selectivity and can selectively remove specific materials while leaving other materials unchanged. This is very important for the processing of complex structures.
Applications of dry etching
- Semiconductor manufacturing: Used for pattern transfer on silicon wafers to form circuits.
- MEMS manufacturing: Structural processing of microelectromechanical systems.
- Optoelectronics: Manufacturing optoelectronic components such as lasers and detectors.
