Low contact resistance metallization for gigabit scale DRAMs usingfully-dry cleaning by Ar/H₂ ECR plasma

摘要

This paper describes a fully-dry cleaning technique withAr/H₂ Electron Cyclotron Resonance (ECR) plasma as a lowcontact resistance metallization technology for gigabit scale DRAMcontacts. Extremely low contact resistances of 296 Ω and 350Ω for 0.3 μm contact diameter with aspect ratio of 7 wererealized on n+ and p+ diffusion layers, respectively. No leakage currentwas observed. By using this technology, a DRAM ULSI, which wasplanarized by Chemical Mechanical Polishing (CMP) and had deep contactholes with aspect ratio of 6, was successfully fabricated