Temperature Dependence of Elemental Depth Profiles at the Au/Si Interface Using Confocal Micro X‐Ray Fluorescence Analysis

Abstract

ABSTRACT This study aims to establish a method for nondestructively evaluating the elemental diffusion behavior at metal/semiconductor interfaces in situ, which is extremely important for reliability assessment of next‐generation semiconductor devices. Confocal micro X‐ray fluorescence spectrometry (CMXRF) was employed to capture the dynamic changes during the heating process, which are difficult to observe using conventional destructive analysis methods such as transmission electron microscopy and Auger electron spectroscopy. Using a gold‐deposited silicon wafer as a model sample, quantitative evaluation of changes in depth distribution under different temperature conditions (60°C, 100°C, and 110°C) was performed using atmospheric‐type and vacuum‐type CMXRF systems. As a result of the experiments, no significant diffusion was observed after heating at 60°C for 9 h. However, under conditions of 100°C and 110°C, a decrease in the peak intensity of the Au Lα line and an increase in the full width at half maximum of the profile were confirmed. Particularly in the in situ measurements at 100°C, we successfully captured the dynamic behavior of Au intensity decreasing within approximately 120 min from the start of heating. These results suggest that CMXRF is an effective method for nondestructively tracking metal diffusion phenomena in semiconductor devices in situ.