Direct Determination of Stress Levels in Sputtered Films by means of X-Ray Diffraction Topographic Method

Abstract

An X-ray topographic method was effectively used to determine stress values as well as the stress nature of thin sputtered films deposited on silicon single-crystal wafers. This method has a simple mechanism, and the stress values can be determined directly from X-ray topographic images without any knowledge of the elastic constants of films. This technique was applied to a determination of the stress levels in iron films and iron nitride films deposited on Si wafers. An iron film sputtered under a low Ar gas pressure has been found to be in a compressive state, while an iron nitride film is in a tensile state. This technique may serve as a monitor for estimating stress levels in such deposited films as new types of chemical vapor deposition (CVD) and physical vapor deposition (PVD) films whose elastic constants are imprecisely known.