Challenges in Root Cause Analysis of Particle Defects

Abstract

The analytical needs in semiconductor technology have grown under the increasing demands imposed by reduced critical dimensions, increased wafer size, and complexity. Optical visualization, localization and counting of particles and defects has been extended to morphological and chemical characterization owing to the shifting balance from quality control to root-cause defect analysis. This becomes increasingly important because, via knowledge of the particle defect material plus the process/ hardware features, it leads to a direct path for the particle culprit and a methodical defect reduction procedure.

We present here specific examples from Applied Materials development, particularly related to particles formed during poly Si etch and during two different cleaning procedures (a) NF3 rf process chamber clean and (b) pre-clean (before subsequent deposition) of SiON film via Ar+ sputtering. These cases include identification of Br-based particles after poly-gate etch, and attempts to classify a variety of Al-containing particles of differing origins caused by too aggressive cleaning.