What This Document Is
This document represents Lecture 7 from the Introduction to MEMS Design (ELENG C245) course at UC Berkeley, focusing on “Process Modules III.” It’s a detailed exploration of various etching techniques crucial for Micro-Electro-Mechanical Systems (MEMS) fabrication. The lecture delves into both wet and dry etching processes, examining the underlying principles and considerations for successful implementation in MEMS device creation. It builds upon previous lectures regarding process modules and expands on the methods used to define structures on silicon wafers.
Why This Document Matters
This material is essential for students and professionals involved in MEMS design and fabrication. It’s particularly valuable when you need a comprehensive understanding of how different materials respond to various etching chemistries. Understanding these processes is fundamental to predicting and controlling the final geometry of MEMS devices. This lecture will be most helpful during the design phase of a MEMS project, when selecting appropriate etching techniques for specific features and materials, and when troubleshooting fabrication issues. Access to the full content will allow for a deeper understanding of the nuances of each process.
Topics Covered
* Anisotropic Wet Etching of Silicon
* Wet Etching of Silicon Dioxide (SiO2)
* Wet Etching of Silicon Nitride
* Wet Etching of Aluminum
* Introduction to Dry Etching Techniques
* Physical Sputtering (Ion Milling)
* Plasma Etching Mechanisms and Chemistry
* Selectivity considerations in etching processes
What This Document Provides
* An overview of different wet etching solutions and their applications.
* Discussion of the impact of crystal orientation on etching rates.
* Examination of the challenges associated with wet etching, and potential solutions.
* An introduction to the principles behind dry etching methods.
* Exploration of the chemical reactions involved in plasma etching.
* Insights into the factors affecting etch rates and selectivity.
* A foundation for understanding the trade-offs between wet and dry etching techniques.
