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Proceedings Paper

Thermal, mechanical, and structural phenomena in laser material interaction by large-scale atomistic modeling
Author(s): Xinwei Wang
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Paper Abstract

Laser material interaction involved in laser-assisted microscale packaging is endowed with rapid and coupled optical, mechanical, and thermal processes. In-depth understanding of the underlying physics in these processes is instrumental for process optimization and functionality and dependability design of systems. This work is focused on the atomistic modeling of laser material interaction, particularly about the phase change, nanoparticle formation, stress generation and propagation, and formation and revolution of sub-surface structural damages. Large-scale parallel molecular dynamics simulation is conducted to model over 200 millions of atoms. The result reveals no clear interface when phase change occurs, but a transition region where the solid and liquid structures co-exist. The solid-liquid interface is found to move with a velocity up to the local sound speed. A vapor and droplet mixture is ejected from the surface with a high speed. The simulation reveals that nanoparticles originate from an intense vapor phase explosion after laser heating. The emerging time of larger particles is much later than that associated with smaller clusters. The resulting nanoparticles are characterized with a gas-like structure while characteristics of liquid are also preserved to a certain degree. In laser-assisted surface nanoscale structuring, visible sub-surface nanoscale structural damages are observed in the direction of 45 degrees with respect to the laser incident direction. Detailed study of the lattice structure reveals atomic dislocation in the damaged regions. Both temporary and permanent structural damages are observed in the material.

Paper Details

Date Published: 12 April 2005
PDF: 14 pages
Proc. SPIE 5713, Photon Processing in Microelectronics and Photonics IV, (12 April 2005); doi: 10.1117/12.596612
Show Author Affiliations
Xinwei Wang, Univ. of Nebraska/Lincoln (United States)

Published in SPIE Proceedings Vol. 5713:
Photon Processing in Microelectronics and Photonics IV
Jim Fieret; David B. Geohegan; Friedrich G. Bachmann; Willem Hoving; Frank Träger; Peter R. Herman; Jan J. Dubowski; Tatsuo Okada; Kunihiko Washio; Yongfeng Lu; Craig B. Arnold, Editor(s)

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