16 April 1993 Etching of TiN local interconnects using HBr in a triode reactor with magnetic confinement
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Proceedings Volume 1803, Advanced Techniques for Integrated Circuit Processing II; (1993) https://doi.org/10.1117/12.142907
Event: Microelectronic Processing '92, 1992, San Jose, CA, United States
Abstract
In CMOS technology for highly integrated circuits, TiN serves as a diffusion barrier layer between the Si substrate and the Al metallization. Structuring the TiN is a challenge as the selectivities of the etching process have not only to be high against resist and SiO2 but also against the gate and S/D materials. For quarter micron devices with shallow p/n junctions this material can be a salicide, e.g., CoSi2 or TiSi2. To address the described requirements, a TiN etch process employing HBr chemistry has been developed in a triode system with magnetic confinement. The reactor concept leads to relatively high ion densities, which allows anisotropic etching at low pressures (5 m Torr) with reasonable TiN etchrates of about 150 nm/min. Selectivities to SiO2 of 5:1 could be obtained. In comparison to Cl2 chemistry the selectivities to photoresist are with 1.5:1 twice as high and allow longer over-etch. Using experimental design software, an optimization with respect to underlying CoSi2 resulted in a selectivity of nearly 10:1 with the drawback of a reduced TiN etchrate. Using the optimized recipe sub-half micrometers TiN structures over high topography have been patterned. The problem of residue removal after resist stripping is discussed.
© (1993) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Gerfried Zwicker, Gerfried Zwicker, Christjan Ursic, Christjan Ursic, Detlef Friedrich, Detlef Friedrich, "Etching of TiN local interconnects using HBr in a triode reactor with magnetic confinement", Proc. SPIE 1803, Advanced Techniques for Integrated Circuit Processing II, (16 April 1993); doi: 10.1117/12.142907; https://doi.org/10.1117/12.142907
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