Secondary ion mass spectrometry backside analysis of barrier layers for copper diffusion

Autor: A. L. Pivovarov, Roberto Garcia, Dieter P. Griffis, James M. Moran, L. Kulig, J. F. Richards, Fred A. Stevie, C. Gu
Rok vydání: 2004
Předmět:
Zdroj: Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures. 22:350
ISSN: 0734-211X
DOI: 10.1116/1.1617278
Popis: Secondary ion mass spectrometry (SIMS) backside analyses have been performed on a Cu/TaN/Ta/SiO2/Si structure to determine barrier effectiveness for Cu diffusion. Sample backside access to the barrier layers was obtained by removal of the Si substrate using a polishing method that maintains parallelism between the sample surface and the polished back side by monitoring changes in facets at the four corners of the specimen. Determination of the Si thickness remaining during the polishing process was improved through the use of optical interference measurements using a narrow band pass optical filter. Samples having slopes with respect to the original surface less than 6 nm over 60 μm have been obtained. A difference in polishing rate between SiO2 and Si was exploited to obtain this parallelism. For SIMS analyses, the presence of a SiO2 layer required electron gun charge neutralization for the O2+ 0.5 keV impact energy analysis. SIMS analyses show the ability to distinguish all layers and to monitor copper ...
Databáze: OpenAIRE