a method for producing a micromechanical device , e . g ., a micromechanical oscillating mirror device , is provided . it is provided , starting from the front side of an soi / eoi substrate , to penetrate to the desired depth of the silicon substrate layer in two successive , separate deep etching steps , and to use this in its upper region that is close to the oxide layer as sacrificial layer for vertically exposing the island structures that are positioned above the oxide layer in the functional layer . the method according to the present invention of a sacrificial layer process for generating large vertical deflections utilizes purely surface micromechanical process steps .