What are the Techniques to Achieve Reduced Undercutting?
Various techniques can be employed to minimize undercutting:
1. Anisotropic Etching: This technique etches material in a highly directional manner, reducing lateral etching and thus undercutting. Common methods include reactive ion etching (RIE) and deep reactive ion etching (DRIE).
2. Hard Masking: Utilizing a hard mask material like silicon nitride or silicon dioxide instead of a soft mask can improve etching precision. Hard masks are more resistant to etching, which helps in reducing the undercutting effect.
3. Optimized Etching Chemistry: Selecting the appropriate etching chemicals can also help reduce undercutting. For instance, using etchants that selectively etch the target material without affecting the mask layer can lead to reduced lateral etching.
4. Process Control and Optimization: Fine-tuning the parameters of the etching process, such as gas flow rates, pressure, and power, can significantly decrease undercutting.
