Process and Equipment Issues in Rapid Thermal Oxidation (RTO)

Abstract

Thin oxides with thicknesses in the range of 150 to 300Å were grown on lOO-mm <100> Si wafers in a commercial RTP reactor. Growth temperatures and times were llO0-1200°C for 60-180 seconds in 100% 02 at 1 atmosphere. Oxide thickness uniformity was measured using ellipsometry; contour maps of thickness uniformity will be presented. The standard deviation wascalculated to be 2-2.5% within 5 mm of the edge using a method which weights the area represented by each of 45 data points per wafer. In order to correct for dynamic changes in temperature uniformity, a new annealing method was developed.Results on wafer-to-wafer uniformity will be presented. Improvements achieved by post-oxidation annealing in N2 and electrical uniformity of films will be discussed.