Adhesion improvement of electroless copper depositions on titanium nitride by low temperature annealing

Abstract

Due to the ever decreasing dimensions of the inter-level metallic interconnects, alternative metal deposition processes must be explored as the current processes (chemical vapor deposition (CVD) and physical vapor deposition (PVDI) are reaching their limits on coverage and uniformity. One such alternative is electronics copper which may be used either to produce a conductive seed layer for electroplating fill or used solely as a fill process. This work attempts to further the knowledge of electronics copper depositions onto titanium nitride, a diffusion barrier material. In particular, an effort is made to characterize the adhesion of the electronics copper deposit on titanium nitride and the improvement of the adhesion produced by low temperature, short duration annealing. The duration of the annealing is varied from 5 to 300 seconds, the temperature varied from 60 to 300C̊, and the thickness of the copper varied from 275 to 400 angstroms. Additionally, work is presented which tries to determine the actual physical mechanism responsible for the improved adhesion after annealing.