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Measuring stresses in thin metal films by means of Raman microscopy using silicon as a strain gage material
Author(s) -
Wermelinger Thomas,
Charpentier Christophe,
Yüksek Müge Deniz,
Spolenak Ralph
Publication year - 2009
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.2332
Subject(s) - materials science , microelectronics , delamination (geology) , raman spectroscopy , composite material , thin film , silicon , stress (linguistics) , diffraction , annealing (glass) , amorphous solid , thermal expansion , optics , optoelectronics , nanotechnology , crystallography , paleontology , linguistics , philosophy , physics , chemistry , biology , subduction , tectonics
Mechanical stresses in microelectronics and micro‐electromechanical systems may influence the reliability of applications and devices. The origin of the stresses can be because of the joining of dissimilar materials with regard to the thermal expansion coefficient, electromigration or the deposition process utilized. Stresses can lead to delamination, crack formation and stress migration and therefore to a failure of the device. Identifying the locations of highest stresses in a device is crucial for reliability improvement. Currently, both Laue X‐ray micro diffraction and convergent‐beam electron diffraction are able to locally determine the stresses in thin metal films. Here, we propose a modified method of indirect Raman microspectroscopy to measure stresses with a lateral resolution in the submicrometer range at a laboratory scale. The method encompasses the crystallization of an amorphous silicon layer by local laser annealing and its subsequent usage as a strain gage. Stresses in an aluminum thin film were determined as a function of temperature. In addition to the average stress, the stress distribution could be monitored. Copyright © 2009 John Wiley & Sons, Ltd.