Oxygen monitors for aluminum and Al–O thin films

Publisher Website
Google Scholar
Abstract
Methods for detecting increases in oxygen concentration in aluminum-based integrated-circuit (IC) metallizations through increases in monitor-film resistivity have been developed. Since the resistivity of the IC film is itself not sensitive to small changes in oxygen concentration, monitor configurations were designed such that the ratio of oxygen-species to aluminum-atom flux on the monitor substrate was many times higher than that on the IC substrates. This resulted in a higher oxygen concentration in the monitor films and a stronger dependence of film resistivity on system oxygen concentration. Monitors were tested in an E-beam evaporator and in an S-Gun magnetron sputtering system during the deposition of aluminum films in a residual-gas environment, and during the deposition of Al–O films deposited with oxygen inputs to the system. Enhancement of the oxygen to aluminum flux ratio was accomplished by shuttering or canting the monitor substrate to decrease the aluminum flux, or by placing it close to the oxygen inlet (in Al–O depositions) to increase the oxygen flux. Monitor resistivity vs flux ratio curves from Al–O depositions have demonstrated the reproducibility of Al–O films and of the oxygen input process. Corresponding curves from residual-gas-only depositions have detected differences in film oxygen concentrations which could not have been detected from pressure measurements.

This publication has 0 references indexed in Scilit: