Online information source for semiconductor professionals

CHRIS MULLER, Purafil, Inc., Doraville, GA, USA

ABSTRACT

As semiconductor device geometry continues to decrease into the deep sub-micron level, chemical contamination has become as important as particulate contamination. Airborne molecular contamination (AMC) can impact almost all aspects of sub-micron device fabrication, from overall fab operation to final device performance. According to SEMATECH’s International Technology Roadmap for Semiconductors [1], the percentage of process steps affected by non-particulate or molecular contamination is expected to increase. Pregate oxidation, salicidation, contact formation, and DUV photolithography have been identified as particularly sensitive production steps. New chemistries introduced to manufacturing processes have also been shown to cause unforeseen AMC-related effects. Hydrogen sulphide, for example, poses a significant threat to the metallisation process as the transition is made from aluminium to copper. As copper appears ready to become the main on-chip conductor for all types of integrated circuits, it is showing up in the plans of chip and production equipment makers worldwide (Figure 1 [2]) and is quickening the shift to AMC-free manufacturing environments.