In order to reduce specific contact resistance at via/interconnect interface and to avoid device degradation with Cu diffusion into dielectrics, via cleaning technology is a critical issue for a scaled down Cu multilevel metallization. Effects of cleaning processes are investigated for CHF3 plasma-etched SiO2/SiN/Cu via-structures. Effects of dilute HF (DHF) cleaning, hydrogen plasma cleaning, oxygen plasma cleaning, hexafluoroacetylacetone (H(hfac)) vapor cleaning, and vacuum anneal cleaning are investigated using an angle-resolved x-ray photoelectron spectroscopy (XPS). Cu contamination removal using dilute oxalic acid (DOA) is investigated using total reflection x-ray fluorescence analysis (TRXRF). Based on the results, we developed an optimized cleaning sequence which consists of a brief oxygen plasma exposure, DHF dipping, followed by exposure to H(hfac) vapors. The cleaning sequence is effective in obtaining a clean dielectric surface and an oxide-free Cu surface at via bottom. Direct-contacted via structures were fabricated by a dual-damascene process using the cleaning sequence. The specific contact resistance reduces to 20% of the reported values. We expect that the via resistance is low enough to be used in 0.13 μm generation and beyond.
|ジャーナル||Materials Research Society Symposium - Proceedings|
|出版ステータス||Published - 1999|
|イベント||Proceedings of the 1999 MRS Spring Meeting - Symposium N: 'Advanced Interconnects and Contacts' - San Francisco, CA, United States|
継続期間: 1999 4月 5 → 1999 4月 7
ASJC Scopus subject areas