Class title( BioMEMS) 5-A generic surface micromachining process is diagramed be
ID: 669703 • Letter: C
Question
Class title(BioMEMS)
5-A generic surface micromachining process is diagramed below, using two layers of structural and two layers of sacrificial materials. In this case, the substrate is silicon, structural layer #1 is gold, and structural layer #2 is parylene. Identify a set of possible candidate materials for sacrificial layer #1 and #2 out of the list of the following materials: LPCVD silicon nitride, LPCVD silicon dioxide, and photoresist. Briefly state the reasoning behind the decision for each item in the list.
Explanation / Answer
Answer:
If Gold is used for structural layer deposition, then Photoresist can be used as the sacrificial layer. Because of the sacrificial etching relies on lateral diffusion in a restricted space. Also free-standing spans of metals are smaller than those of poly and nitride structures.