Eur. Phys. J. AP 22, 3-10 (2003)
https://doi.org/10.1051/epjap:2003018

Interfacial reactions in relation with adhesion failures in Al/TiN/Ti/SiO₂ and Al/TiN/Ti/borophosphosilicate glass systems

¹ TECSEN, UMR CNRS 6122, Université d'Aix-Marseille III, Faculté des Sciences et Techniques de Saint Jérôme, Case 511, 13397 Marseille Cedex 20, France
² ATMEL, Zone Industrielle de Rousset, 13106 Rousset, France

Corresponding author: ahmed.charai@univ.u-3mrs.fr

Received: 5 December 2001
Revised: 10 December 2002
Accepted: 13 December 2002
Published online: 3 April 2003

Abstract

The objective of this work is to determine the origin of a decohesion problem that occurs during the fabrication process of certain integrated circuits. This decohesion takes place at the Ti/dielectric interface with the dielectric being either SiO₂ or borophosphosilicate glass (BPSG). The frequency of the decohesion increased when the dielectric is BPSG. In order to understand the reason for the difference in decohesion rates for the two dielectrics, a comparative study was performed before and after annealing. X-ray Diffraction was used to determine the microstructure of the different layers and Transmission Electron Microscopy coupled to Electron Energy Loss Spectroscopy and X-ray Energy Dispersive Spectroscopy was mainly used to characterize the interfaces and nanophases that had formed during annealing. A fundamental difference observed was the Ti/dielectric interface reactivity: in the case of BPSG, an amorphous layer rich in P is formed before the Ti₅Si₃ silicide. Two hypothesis are put forward in order to explain adhesion failures: a decrease in the rate of Ti₅Si₃ formation kinetics and/or a decrease of the glass transition temperature induced by P enrichment.