is a form of wet etching that uses hydrofluoric acid to etch out surfaces rather than using a dry plasma process. HF etching
is capable of etching materials such as amorphous silicon dioxide; quartz and glass at very high etch rates. Since HF etching
is a wet process, meaning that it uses chemicals, it creates an isotropic etch
. This means that there are curved etched out sections under the etching mask. This is usually not a desirable result because most microfabrication processes require anisotropic etches that plasma etching
is capable of achieving.