ToF-SIMS 3D Analysis of Thin Films Deposited in High Aspect Ratio Structures via Atomic Layer Deposition and Chemical Vapor Deposition

• Main Authors: Alireza M. Kia, Nora Haufe, Sajjad Esmaeili, Clemens Mart, Mikko Utriainen, Riikka L. Puurunen, Wenke Weinreich
• Format: Article
• Language: English
• Published: MDPI AG 2019-07-01
• Series: Nanomaterials
• Subjects: ToF-SIMS 3D imaging; compositional depth profiling; high aspect ratio (HAR) structures; silicon doped hafnium oxide (HSO) ALD deposition; lateral high aspect ratio (LHAR); ToF-SIMS analysis
• Online Access: https://www.mdpi.com/2079-4991/9/7/1035

For the analysis of thin films, with high aspect ratio (HAR) structures, time-of-flight secondary ion mass spectrometry (ToF-SIMS) overcomes several challenges in comparison to other frequently used techniques such as electron microscopy. The research presented herein focuses on two different kinds of HAR structures that represent different semiconductor technologies. In the first study, ToF-SIMS is used to illustrate cobalt seed layer corrosion by the copper electrolyte within the large through-silicon-vias (TSVs) before and after copper electroplating. However, due to the sample’s surface topography, ToF-SIMS analysis proved to be difficult due to the geometrical shadowing effects. Henceforth, in the second study, we introduce a new test platform to eliminate the difficulties with the HAR structures, and again, use ToF-SIMS for elemental analysis. We use data image slicing of 3D ToF-SIMS analysis combined with lateral HAR test chips (PillarHall™) to study the uniformity of silicon dopant concentration in atomic layer deposited (ALD) HfO₂ thin films.