Depth profile analysis of aluminium metallization in microelectronics: Optimization of depth resolution

Depth profiling of aluminium metallization in microelectronics devices by Auger or SIMS analysis is impeded by the severe sputter‐induced roughening which causes a serious loss in depth resolution. This paper discusses strategies to avoid this deteriorating effect: optimization of the bombardment angle, sample rotation during sputtering and the use of heavy or reactive ions. The best depth resolutions were achieved by sputtering with normal incidence 15 keV O 2 + ions. In this case, an interface width of 12 nm was measured for a film of 1 μm thickness. This is an improvement by more than a factor of 10 compared to the extremely poor depth resolution of 160 nm resulting from routine analysis parameters (Ar + ions incident at 55°).