Chemical tomography for advanced manufacturing
Karen T. Henry, Eric Steel and Ian Anderson
As semiconductor device architectures continue to decrease in size, the ability to measure the position and composition of individual atoms becomes increasingly critical. With fewer dopant atoms within such devices, quantitative analysis with current techniques becomes increasingly difficult. Atom probe tomography is one of the few methods available to analyze and image solid materials at the atomic scale yielding full elemental and position information in three dimensions (3D). For continued advancements in semiconductor manufacturing, the development of atom probe tomography into a reliable metrology technique will be a necessity.
This research addresses the challenge presented above of quantifying the position and elemental identity of individual atoms within a 3D nanostructure. The local electrode atom probe (LEAP) coupled with a pulsed UV laser has allowed for data acquisition of semiconducting and insulating materials previously inaccessible by traditional voltage-pulsed atom probe. Optimization of sample preparation, experimental conditions and data analysis for use in the manufacturing of 3D transistors has also been addressed by this research. This technique is positioned to provide key information in the design, quality control and failure analysis of manufactured devices. We report on the advances and limitations of chemical tomography for 3D nanostructures using atom probe tomography.