Analysis of the composition of tantalum nitride in CMOS metallization trenches using parallel angle‐resolved XPS

Abstract

We demonstrate the utilization of parallel angle-resolved X-ray photoelectron spectroscopy (pAR-XPS) as a useful tool to analyze ultrathin sputtered tantalum nitride (TaN) thin films in complementary metal-oxide-semiconductor (CMOS) trenches. The chemical composition of TaN was estimated by pAR-XPS using a Theta 300i from Thermo Fischer. An improved lateral resolution was achieved by analyzing periodic structures. The XPS data was correlated with transmission electron microscopy (TEM) in combination with energy-dispersive X-ray spectroscopy (EDX) and time-offlight secondary ion mass spectrometry (ToF-SIMS) data. The results show that the nitrogen content in the TaN thin films was about 6% higher at the sidewall compared with the top and bottom of the trench.