1. Comprehensive Chemistry Designs in Porous SiOCH Film Stacks and Plasma Etching Gases for Damageless Cu Interconnects in Advanced ULSI Devices.
- Author
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Hayashi, Yoshihiro, Ohtake, Hiroto, Kawahara, Jun, Tada, Munehiro, Saito, Shinobu, Inoue, Naoya, Ito, Fuminori, Tagami, Masayoshi, Ueki, Makoto, Furutake, Naoya, Takeuchi, Tsuneo, Yamamoto, Hironori, and Abe, Mari
- Subjects
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INTEGRATED circuit interconnections , *COPPER , *PLASMA etching , *ULTRA large scale integration of circuits , *SEMICONDUCTOR manufacturing , *SEMICONDUCTOR industry - Abstract
High performance Cu dual-damascene (DD) interconnects without process-induced damages are developed in porous SiOCH stacks with the effective dielectric constant (keff) of 2.95, in which a carbon (C)-rich molecular-pore-stacking (MPS) SiOCH film (k = 2.5) is stacked directly on an oxygen (O)-rich porous SiOCH (k = 2.7) film. The novel etch-stopperless structure is obtained by comprehensive chemistry design of C/O ratios in the SiOCH stack and the etching plasma of an Ar/N2/CF4/O2 gas mixture technique. Large hydrocarbons attached to hexagonal silica backbones in the MPS-SiOCH prevent the Si-CHx bonds from oxidation during O2-plasma ashing, suppressing the C-depleted damage area at the DD sidewall. Combining multiresist mask process with immersion ArF photolithography, strictly controlled Cu DD interconnects with 180-nm pitched lines and 65-nm-diameter vias are obtained successfully, ready for the 300-mm fabrication. [ABSTRACT FROM AUTHOR]
- Published
- 2008
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