Finite Element Models for Extracting Mechanical Properties of ILD Stack from Indentation Tests
Research Report Highlight
An inverse finite element analysis technique has been used to estimate the yield strength of a metal film buried under an ILD stack. This indentation technique greatly simplifies sample generation since it does not require a free standing film.
The fabrication process-induced variation in the yield strength of metal films in microelectronic devices critically impacts the reliability of inter-layer dielectric (ILD) stacks. However, estimation of the yield strength of buried films in multilayer stacks remains a significant challenge. The indentation technique, whose advantage is that it does not require a free-standing film, has been widely used to characterize thin films, but traditional analysis mostly focus on characterizing the top layer of the stack. In this report, we describe an optimization-based inverse finite element analysis (IFEA) technique to estimate the yield strength of a buried metal film in the ILD stack. The technique is demonstrated by estimating the yield strength of the buried aluminum film in a TEOS-Al-Si3N4-Si stack.