Challenges of plasma damage of low dielectric constant materials

PMSE 446

Mikhail R. Baklanov,, Adam M. Urbanowicz,, and Serge Vanhaelemeersch, AMPS, IMEC, Kapeldreef 75, B-3001 Leuven, Belgium
Low dielectric constant (low-k) materials are required as interlayer dielectrics for on-chip interconnects of ULSI devices to provide high speed, low dynamic power dissipation and low cross-talk noise. Selecting chemical compounds with low polarizability and introducing porosity achieve reduction of dielectric constant. However, porosity of low-k materials creates challenges during their integration in ULSI devices because of diffusion of active species into the film during different chemical and plasma treatments. In this work, experimental results showing plasma damage in different plasma reactors are presented. The observed phenomena are well described by diffusion-recombination model. It is demonstrated that the depth of damage can be significantly reduced by generation of surface active centers that increase the probability of recombination of active radicals. Creation of these active centers by VUV photons emitted by He plasma is also discussed.