The goal of wet chemical processing is the straightforward, cost effective fabrication of microstructures.
- Wet chemical cleaning of substrates (Silicon, Borofloat, Quartz,…)
- Anisotropic etching of silicon
- Patterning of metals (Al, Au, Ag, Cr, Cu, Ti, W/Ti, Ni,…)
- Patterning of various glass materials
- Use of standardized etchants in semiconductor applications
- Fast and specific etchant development for specialized applications
- Fabrication of conducting traces
- Fabrication of functional optical structures
- Fabrication of anisotropic silicon structures
Wet chemical etching refers to removal of solids by dissolving them in a chemical solvent. The layers and substrates to be etched are often first patterned through photolithography, such that only the areas to be etched are attacked by the solvents. In practice, the substrates are either dipped into an etch bath or sprayed with an etchant. Dipping into an etch bath can be carried out for multiple substrates simultaneously (batch processing), while spray etch processes can only be carried out on single substrates at a time.
Single crystal materials can be etched anisotropically and independent of doping using selected etchants such as KOH and NaOH.
In general, wet chemical etching is preferred due to the high selectivity, low contamination and low damage to surfaces that it provides. Further advantages include uniformity and reproducibility, as well as a well controlled etch rate.
Relatively straightforward and low cost infrastructure is needed for wet chemical etching, and several substrates can be processed at the same time.