MONITORING ELECTRICALLY ACTIVE CONTAMINANTS TO ASSESS OXIDE QUALITY

Demands for higher product performance have resulted in device designs with narrower line-widths and thinner dielectric materials for faster operation and lower operating voltages, Consequently, the sensitivity to defects and contaminants caused by process variabilities has incre ased. The Semiconductor Industry Association's 1994 Technology Roadmap projects that surface ionics must drop to <2.5 x 10(10) and surface m etals to <1.0 x 10(10) atoms/cm(2) by 2001. As a result, tighter contr ols on contamination must be achieved to meet the electrical performan ce levels that future generations of products will demand. Because ele ctrical performance is the ultimate measure of quality, techniques tha t measure electrically active contaminants in oxides in MOS processing are essential. The corona-oxide-semiconductor technique measures a va riety of parameters rapidly and can be used in-line to monitor oxide c harge contaminants. This article discusses the relative merits of esta blished and emerging oxide-charge contamination measurement techniques .