ABSTRACT
Chapter 4 is split in two parts: one part deals with wet chemical etching and the other with wet bulk micromachining. Both these subtractive manufacturing techniques cover purely chemical etching, photochemical etching, electrochemical etching, and combinations thereof. Wet bulk micromachining is derived from chemical etching, but wet etching and bulk micromachining are typically used in very different industrial settings. In chemical etching, one carves isotropic features, large (milling) and small (blanking), out of metals, glasses, polymers, and ceramics. The technique is mostly used in more traditional industrial manufacturing settings such as aerospace, electronics, automotive, medical, computer, instrument manufacturing, and decorating. Wet bulk micromachining, on the other hand, is used to sculpt isotropic and anisotropic microstructures principally in semiconductors substrates. It is a technique championed in the integrated circuit (IC) industry and in micro-and nanomachining.
