Method for HF Vapor Release of Micromachined Structures

A wet and vapor acid etching method releases a microelectromechanical systems (MEMS) structure from a substrate by dissolving a sacrificial layer disposed between the MEMS and the substrate. The sacrificial layer may be a silicon dioxide (SiO2) layer having a field portion over which the MEMS does not extend and a support portion over which the MEMS does extend. The field portion of the SiO2 layer is quickly removed using conventional wet hydrofluoric (HF) etching followed by rinsing and drying and then the support portion is removed using conventional vapor HF etching from a solution greater than 45% by weight percent. The wet HF chemical etch quickly removes the large field portion of the sacrificial layer. The HF vapor etch removes the small support portion of the sacrificial layer below the MEMS to release the MEMS from the substrate without stiction thereby preventing damage to the MEMS when released.