Hängendes Bauelement und Herstellungsverfahren

摘要

A substrate (102) defining a cavity comprising a wide, shallow first portion (104) and a narrow, deep second portion (103) is provided. The first portion of the cavity extends into the substrate from the front side of the substrate and is filled with sacrificial material (105). The second portion extends deeper into the substrate from the first portion. A device structure (110) is fabricated over the sacrificial material. A release etchant is introduced from the back side of the substrate via the second portion of the cavity to remove from the first portion of the cavity the sacrificial material underlying the device structure. Thereby the release etch can be performed without exposing the device structure to the release etchant. This allows the device structure to incorporate materials that have a low etch selectivity with respect to the sacrificial material.