Unformatted text preview: ainly due to edge defects
Figure Credit: (Top) A. Danilewsky, J. Wittge, K. Kiefl, D. Allen, P. McNally, J. Garagorri, M.R. Elizalde, T. Baumbach, B.K. Tanner, Crack propagation
and fracture in silicon wafers under thermal stress, Journal of Applied Crystallography, Vol. 46, Part 4, August 2013, Pages 849-855
(Bottom) Kurt E. Peterson, Silicon as a Mechanical Material, Proceedings of the IEEE, Vol. 70, No.5 May 1982, Page 421 Results of Different Etchant Systems Etch Stops
• Doped layers buried in epitaxial layers • Anisotropic etching stops at doped layer.
• Depth of hole determined by thickness of epi-layer. DEFINITION
• Thermomigration is the movement of alumina on silicon towards the hotter side of a wafer with a temperature gradient.
• At sufficiently high temperatures, alumina on silicon forms a molten alloy.
• The silicon on the wafer begins to dissolve on the hot side and the Al/Si alloy migrates to take its place. start PROCESS
• Glass slide placed over wafer (bare or oxidized)
• Assembly is heated to 400 °C
• High voltage applied between silicon and metal contact on glass (~1200 V) Optical Benches and
• Long V grooves in wafers are crucial for alignment of small optical fibers
• Fibers can be attached together or precisely aligned to surface features V Groove Miniature Circuit Board
Packaging Density of silicon chips can be increased by using silicon as miniature pluggable circuit boards Silicon Wafers with Anisotropically e...
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This note was uploaded on 02/03/2014 for the course ME 119 taught by Professor Lwlin during the Spring '08 term at Berkeley.
- Spring '08
- Mechanical Engineering