In the semiconductor industry, titanium nitride is often used as an inorganic hard mask, enabling the robust creation of structures (vias) with widths down to at least 5 nm. After the vias are created, using plasma etching techniques, the hard mask has to be removed again, as its presence during final manufacturing steps would severely impact device performance.<br/><br/>In general, the TiN layer is removed using oxidative etching chemistry. With differentiation between chip manufacturers increasing over the past years, multiple types of TiN are used, mostly differing in deposition technique. These different types of TiN show vastly differing etch rates and underlying mechanisms.<br/><br/>In this paper, we present data on the oxidative etching of TiN, in which the deposition techniques and conditions were varied (PVD, CVD, ALD), as well as the oxidative etching chemistry. We discuss the impact of the deposition technique and composition on the etch rates, film morphology, thermodynamic parameters and underlying mechanisms for various products, and show that tuning of both the TiN film composition and the applied etch product results in a broad range of applicable chemistries which can be used in cutting-edge chip manufacturing technologies.

TiN etching in the semiconductor industry: Effects of material deposition and etch compositions

256th National Meeting (2018)

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