Plasma Diagnostics of Discharges in Nitrogen-Trifluoride (Etching, Semiconductor)

This work has dealt with an investigation of the nitrogen trifluoride etchant gas discharge and has demonstrated a variety of diagnostic techniques applicable to all plasmas used for semiconductor processing. By monitoring the change of the mass spectrum ion signals when the discharge was initiated, it was found that the discharge is much more effective at dissociating NF(,3) than CF(,4) and that the percentage dissociation of the NF(,3) can be quite large, greater than 50%. The negative ion density in the NF(,3) plasma was determined by photodetaching the electrons from the negative ions and measuring the photodetached electron density with microwave interferometry. The steady state negative ion density was found to be 50 times larger than the steady state electron density. Finally, the kinetics of product formation were examined by observing the optical emission from a pulsed discharge as a function of time and current. The formation studies suggested that the primary source of atomic fluorine in the NF(,3) discharge was the direct electron impact dissociation of the parent gas. A model describing the dissociation and product formation is presented.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Electrical Engineering

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2014

Author dc:creator

• Greenberg, Kenneth Eli

• Engineering, Electronics and Electrical

Identifier

(UMI)AAI8502157

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/69290