This chapter presents methods used in the fabrication of MEMS. Many are borrowed from the integrated-circuit industry, in addition to others developed specifically for silicon micromachining. There is no doubt that the use of process equipment and the corresponding portfolio of fabrication processes initially developed for the semiconductor industry has given the burgeoning MEMS industry the impetus it needs to overcome the massive infrastructure requirements. For example, lithographic tools used in micromachining are oftentimes from previous generations of equipment designed for the fabrication of electronic integrated circuits. The equipment's performance is sufficient to meet the requirements of micromachining, but its price is substantially discounted. A few specialized processes, such as anisotropic chemical wet etching, wafer bonding, deep reactive ion etching, sacrificial etching, and critical-point drying, emerged over the years within the MEMS community and remain limited to micromachining in their application.

From a simplistic perspective, micromachining bears a similarity to conventional machining in the sense that the objective is to precisely define arbitrary features in or on a block of material. There are, however, distinct differences. Micromachining is a parallel (batch) process in which dozens to tens of thousands of identical elements are fabricated simultaneously on the same wafer.