US Patent 9768033 Methods for high precision etching of substrates

This disclosure relates to a plasma processing system and methods for high precision etching of microelectronic substrates. The system may include a combination of microwave and radio frequency (RF) power sources that may generate plasma conditions to remove monolayer(s). The system may generation a first plasma to form a thin adsorption layer on the surface of the microelectronic substrate. The adsorbed layer may be removed when the system transition to a second plasma. The differences between the first and second plasma may be include the ion energy proximate to the substrate. For example, the first plasma may have an ion energy of less than 20 eV and the second plasma may have an ion energy greater than 20 eV.