Deep Reactive Ion Etching (DRIE or ASE; patented by Robert Bosch GmbH) is a silicon etching process enabling the manufacturing of structures with high aspect ratios. The process is based on an alternating ion etching and sidewall passivation of structures. Protron's engineers have many years experience in development and manufacturing of MEMS with DRIE. The process is the most versatile silicon bulk micromachining process in microsystem technologies. It allows the realization of 3-dimensional structures with a high degree of design freedom. Protron uses the process for the realization of devices in almost every field of MEMS applications, such as microfluidics, microoptics, sensors, and actuators.