Case Study of Micro-Contamination Control

Abstract

Airborne contaminants (gases and particles) pose serious threats to hi-tech industries with the critical dimension of a micro-electronics chip quickly shrinking to nano-scale and the glass substrate of an LCD panel substantially enlarging to 1.9 m by 2.2 m (Generation 7.5). Due to the fast technology evolution, the cleanliness requirement of cleanroom air quality is highly critical. For example, for the 45 nm technology node, ammonia concentration is required to be less than 2.5 part-per-billion (ppb) and concerned particle size is down to 23 nm. To tackle the contamination problem for the rapidly evolving processes, the related information and technique should be shared and learned quickly. In this study, four cases of contamination control are described and they are: (1) corrosive gases (e.g., HBr, HCl, HF, SiF4) outgassing from newly dry-etched wafers, (2) gas leaking from an exhaust pipeline in a semiconductor cleanroom, (3) optical lens hazed by fine particles in a thin-film-transistor liquid-crystal-display (TFT-LCD) fab, and (4) re-entrained boron contaminating the glass substrates inside an LCD stocker. By sharing the case scenarios, it is expected that similar micro-contamination problems could be avoided and the product yield be enhanced. Besides, new monitoring and control techniques for micro-contamination might also be developed based on the results found in this study.