Elastic recoil detection using time-of-flight for analysis of TiN/AlSiCu/TiN/Ti contact metallization structures

Abstract

The ability of elastic recoil detection (ERD) with time-of-flight (TOF) to quantify multilayer TiN/AlSiCu/TiN/Ti contact metallization structures on Si and SiO 2 has been demonstrated. In the technique a single microchannel plate (MCP) detector assembly and a silicon surface barrier detector (SSBD) were used. Technically high quality multilayer structures that have important applications in VLSI/ULSI devices were produced in a commercial Varian M2000 cluster tool by sputtering techniques. Several device process parameters such as annealing temperature (450°C, 500°C and 550°C), TiN oxidation, TiN ARC layer, TiN diffusion barrier thickness (50 and 90 nm) and types of substrate (Si and SiO 2) have important consequences on the performance of the product. The effect of changes in the above mentioned parameters on the elemental composition have been reliably studied by ERD. All the elements from H to Cu including substrate Si of a contact structure have been quantitatively and simultaneously profiled in a single experiment. The reproducibility of the major concentrations (N, O, Al, Si and Ti) in a multilayer test sample in every batch was within ±5%. Grazing angle X-ray diffraction (XRD) and the analyses of the ternary and quaternary phase diagrams complemented by the ERD investigations have been used to identify various phases in the layers. These results were then correlated with the measured electrical properties.