Reduction of Oxygen Plasma Damage by Postdeposition Helium Plasma Treatment for Carbon-Doped Silicon Oxide Low Dielectric Constant Films

Abstract

The low dielectric constant (low k) carbon doped silicon oxide (CDO) films are obtained by plasma-enhanced chemical vapor deposition. The impact of oxygen plasma treatment on the properties of low k films has been investigated and it is found that O 2 plasma treatment damages the CDO film by removing C and part of Si contents in the film. This results in the loss of film thickness and increase in k value of the film. Postdeposition He plasma treatment has been confirmed to be effective in reducing the O 2 plasma damage on the CDO films significantly. With He plasma pretreatment, the thickness loss after O 2 plasma is reduced, and k value remains the same as the as-deposited CDO film compared to the film without the He plasma pretreatment. Also analysis of film properties by Fourier transform infrared spectroscopy. secondary ion mass spectrometry, atomic force microscopy, and scanning electron microscopy indicates that there is no obvious change of the properties of low k CDO films after O 2 plasma for postdeposition He plasma pretreated films.