Effect of top corner rounding in BEOL to yield in advanced technologies

In advanced technologies as the dimensions shrink, even the slight change in profiles can cause issues in BEOL integration. This paper discusses the effect of dielectric profile on product yield. Even though these issues were not seen on standard monitoring structures, the issue has been observed in products of very complicated design structures. The yield losses for this failure mechanism range from 10% to 20%. The fails being more of a functional fail than a physical failure made the problem even more complicated. Here we discuss how the issue was identified by data mining, followed by in depth investigation on individual module and understanding the interactions. By understanding the interaction between process modules, an optimized and manufacturable solution was derived and implemented. The issue was addressed by optimizing the film treatment and the wet-clean optimization, as an integrated module approach. Yield was verified on this optimized process and proven.