New solutions for intermetal dielectrics using trimethylsilane-based PECVD processes

Trimethylsilane, (CH3)(3)SiH, is a non-pyrophoric organosilicon gas. This material is easily used to deposit dielectric thin films in standard PECVD systems designed for SiH4. In addition to deposition of standard dielectrics (e.g. SiO2), trimethylsilane can be used to deposit reduced permittivity (low-k) dielectric versions of amorphous hydrogenated silicon carbide and its oxides. The low-k carbides (k < 5.5) are highly insulating and useful as hard masks, etch stops and copper diffusion barriers. The low-k oxides (2.6 < k < 3.0) are useful as intermetal dielectrics, and exhibit stability and electrical properties which can meet many specifications in device fabrication that are now placed on SiO2. This paper reviews PECVD processing using trimethylsilane. Examples will show that the 3MS-based dielectrics can be used in place of SiH4-based oxides and nitrides in advanced device multilevel metal interconnection schemes to provide improved circuit performance. (C) 2000 Elsevier Science B.V. All rights reserved.