Micromachining of detailed silicon structures on thin membranes is considered to be a principal microelectromechanical system (MEMS) fabrication technique. However, it is a highly difficult process.
When the membrane is approached, there is a notable decrease in lateral heat dissipation from the etching structures on a membrane. This causes the silicon to clear from the membrane layer, leading to a sharp change in the chemical loading effect. In case the associated heat is concentrated in a small area, then the exothermic etch reaction can also lead to degradation of the etch passivation and the resist pattern.