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

Electron Energy Distribution;Ion Energy Distribution;Inductively Coupled Plasma;Pulsed Power;Electrical Engineering;Engineering;Electrical Engineering

Logue, Michael DavidBoyd, Iain D. ;

University of Michigan

关键词: Electron Energy Distribution;    Ion Energy Distribution;    Inductively Coupled Plasma;    Pulsed Power;    Electrical Engineering;    Engineering;    Electrical Engineering;   

Others  :  https://deepblue.lib.umich.edu/bitstream/handle/2027.42/108890/mdlogue_1.pdf?sequence=1&isAllowed=y

瑞士|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

In order to meet present and upcoming challenges to reduce feature sizes below 22 nm, advanced plasma etching techniques are required, necessitating 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 rates of electron impact reactions that generate reactive species from feedstock gasses. Ions enable very directional etches with near vertical sidewall profiles. Ions are accelerated vertically toward the substrate through sheaths. The greater the potential drop across the sheath, the greater the ion acceleration and the greater the energy with which it bombards a substrate. IED control is an important factor in controlling etch profiles and reducing plasma induced damage.Two potential methods to control EEDs and IEDs in inductively coupled plasmas (ICPs) are discussed using results from a 2-D hybrid model, the Hybrid Plasma Equipment Model (HPEM). These methods include the use of pulsed ICP power and dc biases on electrodes in contact with the plasma. Modifications are made to the HPEM to enable more accurate EED calculations in systems with multiple ICP coilsets as well as more accurate IED calculations in systems with pulsed ICPs and/or pulsed dc biases. Pulsed plasmas provide a way to obtain EEDs on a temporal as well as a time averaged basis that might not be accessible with continuous wave (cw) excitation. Pulsed power modulates the tail of the EED and allows for modulation of the source functions for reactive species that are the result of processes with higher threshold energies. The application of dc bias onto electrodes in contact with the plasma shifts the plasma 1potential by approximately the dc bias voltage with a corresponding shift in the peaks of the IED. Biases can be applied in continuous or pulsed formats and combined with pulsing of the ICP power for even greater control of EEDs and IEDs.