Abstract: According to the invention there is provided a method of plasma etching a silicon-based compound semiconductor substrate, the method comprising providing the substrate within an etch chamber and performing a cyclical process on the substrate, each cycle comprising supplying an etchant gas into the chamber, energising the gas into a plasma, and performing an etch step on the substrate using the plasma; and performing a desorption step, wherein during the desorption step, the only gas that is supplied into the etch chamber is an inert gas, so as to allow reactive species that have adsorbed to the surface of the substrate during the etch step to desorb from the surface of the substrate.

Abstract: A method and system are for monitoring and controlling deformation of a wafer substrate during a plasma etching of the wafer substrate. The method includes disposing a wafer substrate on a platen assembly within a process chamber so that an entire upper surface of the wafer is exposed, passing a process gas into the process chamber, applying a radio frequency bias voltage to the platen assembly, generating a plasma within the process chamber, monitoring a voltage difference between the platen assembly and the process chamber, during the etch process, and attenuating or extinguishing the plasma to prevent further etching once a threshold monitored voltage is reached.