Abstract
Adhesion strength of dissimilar materials at their interfaces determines mechanical reliability of micro- and nano-scale devices. Various methods have been proposed and utilized to measure adhesion strength. However, they are mostly based on macroscopic application of delamination stresses at interfaces. On the other hand, a nano-scratch technique has a potential to measure adhesion strength in a much smaller scale. This paper presents some examples of the experimental results obtained by nano-scratch test. An excellent correlation was found between the measured adhesion strength and themicrostructure observed by transmission electron microscopy. Finite element calculation of stress distribution during nano-scratch test indicated that a large tensile stress is concentrated at the interface ahead of the indenter tip. The stress concentration was limited in a small region of approximately 50nm on the interface plane. The results suggest that the nano-scratch test is capable of measuring adhesion strength in a 50-nm scale.
