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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