Organofluorosilicate glass: A dense low-k dielectric with superior materials properties

Organofluorosilicate glass (OFSG) films with the composition Si:O:C:H:F were deposited using plasma-enhanced chemical vapor deposition (PECVD) using the mixtures of trimethylsilane (3MS), silicon tetrafluoride (SiF4) and oxygen (O2). OFSG films have better mechanical strength, thermo-oxidative stability and adhesion ability as compared with those of organosilicate glass (OSG) films deposited from 3MS and O2. We found that the increased density of OFSG films, which helped improving mechanical strength, was balanced by the presence of non-polarizable Si–F functionality, which leads to a lower dielectric constant and appeared to be a promising low-k material for interlayer dielectrics application.