Step coverage of rf-diode-sputtered SiO2 films

Abstract

Step coverage profile dependences of rf-diode-sputtered SiO2 films on deposition parameters have been examined by SEM observations. The obtained results are summarized as follows: (1) With decreased spacing between substrate and target, slope of step coverage changes from negative to positive through vertical. (2) Decreasing argon pressure improves step coverage, resulting in a positive slope. (3) Negative dc voltage application to substrate holder makes step coverage negative. On the other hand, step coverage is improved at positive dc voltage. (4) Putting shield ring on substrates, smooth and positive slopes are obtained. The obtained results are successfully explained by shadowing effect of incidence SiO2 materials by substrate step.