Control of Electron and Ion Energy Distributions in Inductively Coupled Plasmas Using Pulsed Power and dc Biases For Fabrication of Microelectronics

In order to meet present and upcoming challenges to reduce feature sizes below 22 nm, advanced plasma etching techniques are required, with tighter control over plasma properties and etch characteristics. Better control of the electron energy distribution (EED) and the ion energy distribution (IED) are two ways to help achieve this goal. The EED controls plasma properties such as electron temperature and plasma density as well as the generation rates of reactive species from feedstock gasses. IED control is an important factor in controlling etch profiles and reducing plasma induced damage.
The use of pulsed ICP power, as well as dc biases on electrodes in contact with the plasma, to control EEDs and IEDs in inductively coupled plasmas (ICPs) will be discussed. Pulsed power modulates the tail of the EED and allows for modulation of the source functions for reactive species generated by high threshold energy processes. Application of dc biases onto electrodes in contact with the plasma shifts the plasma potential by approximately the dc bias voltage with a corresponding shift in the peaks of the IED. Results from investigations of these two control methods using a 2-D hybrid model, the Hybrid Plasma Equipment Model (HPEM), will be discussed.