  In this review article we consider the crack growth resistance ofmicrometer
and submicrometer sized samples from the fracture mechanics point of view.
Standard fracture mechanics test procedures were developed for macroscale
samples, and reduction of the specimen dimensions by three to five orders of
magnitude has severe consequences. This concerns the interpretation of results
obtained by micro and nanomechanics, as well as the life time and failure
prediction of micro and nano devices. We discuss the relevant fracture
mechanics length scales and their relation to the material specific structural
lengths in order to conduct rigorous fracture mechanics experiments. To ensure
general validity and applicability of evaluation concepts, these scaling
considerations are detailed for ideally brittle, semi brittle and micro ductile
crack propagation, subject to both monotonic and cyclic loading. Special
attention is devoted to the requirements for determining specimen size for
various loading types to measure material characteristic crack propagation
resistance at small scales. Finally, we discuss novel possibilities of micron
and submicron fracture mechanics tests to improve the basic understanding of
specific crack propagation processes.
