Reliability results on a 0.25 micron aluminum backend with a TiN sidewall

As device dimensions shrink in semiconductor technology, new tools and techniques are needed to solve reliability issues due to small overlap tolerances. For the 0.25/spl mu/m technology and beyond, titanium nitride (TiN) chemical vapour deposition (CVD) tools and processes were developed to improve the reliability of unlanded vias with small overlap tolerances in these processes. These tools are expensive to implement for smaller companies. In this paper, a financially preferable solution using more conventional physical vapor decomposition (PVD) equipment already in use and the associated resulting reliability analysis is presented. Depositing and anisotropically etching PVD TiN can create a protective sidewall on the underlying metal prior to the deposition of the inter-metal dielectric (IMD). The resulting reliability of via strings in extreme misaligned (unlanded) conditions with and without this sidewall is examined.