There is provided a method of producing a microstructure that comprises employing a hydrogen fluoride (HF) vapour to etch a sacrificial layer of silicon dioxide (SiO.sub.2) and thereafter removing a residual layer formed when HF vapour etching the layer of silicon dioxide. The residual layer may comprise silicon, ammonium salt or carbon and various techniques are disclosed for removing such layers. These techniques may be applied concurrently, or sequentially, to the microstructure. The described methodologies therefore produce microstructures that exhibits reduced levels of residue when as compared to those techniques known in the art.