Etching of TiN local interconnects using HBr in a triode reactor with magnetic confinement

Gerfried Zwicker; Christjan Ursic; Detlef Friedrich

doi:10.1117/12.142907

16 April 1993 Etching of TiN local interconnects using HBr in a triode reactor with magnetic confinement

Gerfried Zwicker, Christjan Ursic, Detlef Friedrich

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.

Citation Download Citation

Gerfried Zwicker, Christjan Ursic, and 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); https://doi.org/10.1117/12.142907

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