Gerardo A. Delgadino

Frequency optimization for capacitively coupled plasma source

Design of an all-in-one (main etch, PR ash and clean) dielectric etch chamber requires independent control of plasma generation from ion energy. Plasma simulation has been performed for a capacitively coupled discharge to study frequency effect on electron density, power deposition, and dissociation fraction. Simulation results demonstrate that plasma production efficiency enhances with increase in frequency while energy of the bombarding ions diminishes. A very high frequency source has been developed to generate high density plasma while radio frequency bias has been used to control ion energy. As illustrated, the etch rate for a dual damascene trench etch process increases, while damage due to ion bombardment is reduced. The dissociation fraction is well behaved to provide necessary corner protection. High-frequency source was used to achieve better performance for dual damascene trench etch process.

Plasma Simulation for High Frequency Plasma Source Design and Process Development

Summary form only given. Plasma simulation has been performed for a capacitively coupled discharge to study frequency effect on electron density, power deposition, and dissociation fraction. Simulation results demonstrated that plasma production efficiency improves with an increase in frequency while ion bombardment energy diminishes. At very high frequency, plasma generation can be controlled independent of ion energy. A very high frequency source has been developed that generates high-density plasma while RF bias is used to control ion energy. Process data showed that the etch rate for a dual damascene trench etch process increases while damage from ion bombardment is reduced. Simulation of plasma clean demonstrated higher species flux at lower pressure and higher source power. Process data confirmed that plasma cleaning is more efficient under these conditions. Thus, plasma simulation focused the selection of source frequency and helped optimize hardware and process design to make possible an effective all-in-one sequence of main etch, ash, and clean