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Three-Dimensional Measurement of Line Edge Roughness in Copper Wires Using Electron Tomography.
- Source :
- Microscopy & Microanalysis; Jun2009, Vol. 15 Issue 3, p244-250, 7p, 4 Diagrams, 3 Graphs
- Publication Year :
- 2009
-
Abstract
- Electrical interconnects in integrated circuits have shrunk to sizes in the range of 20-100 nm. Accurate measurements of the dimensions of these nanowires are essential for identifying the dominant electron scattering mechanisms affecting wire resistivity as they continue to shrink. We report a systematic study of the effect of line edge roughness on the apparent cross-sectional area of 90 nm Cu wires with a TaN/Ta barrier measured by conventional two-dimensional projection imaging and three-dimensional electron tomography. Discrepancies in area measurements due to the overlap of defects along the wire's length lead to a 5% difference in the resistivities predicted by the two methods. Tomography of thick cross sections is shown to give a more accurate representation of the original structure and allows more efficient sampling of the wire's cross-sectional area. The effect of roughness on measurements from projection images is minimized for cross-section thicknesses less than 50 nm, or approximately half the spatial frequency of the roughness variations along the length of the investigated wires. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 14319276
- Volume :
- 15
- Issue :
- 3
- Database :
- Complementary Index
- Journal :
- Microscopy & Microanalysis
- Publication Type :
- Academic Journal
- Accession number :
- 41980637
- Full Text :
- https://doi.org/10.1017/S143192760909028X