Prakt. Met. Sonderband 46 (2014) 27
NOVEL METHODS FOR THE SITE SPECIFIC PREPARATION OF
MICROMECHANICAL STRUCTURES
S. Wurster*, R. Tremi* **, R. Fritz“, M. W. Kapp***, E.-M. Langs*, M. Alfreider*, C. Ruhs**
P.J. Imrich***, G. Felber*, D. Kiener*
* Department Materials Physics, Montanuniversitat Leoben, Leoben, Austria
of Metals. ** Materials Center Leoben, Leoben, Austria
*** Erich Schmid Institute, Austrian Academy of Sciences, Leoben, Austria
etallurgical and Materials
ABSTRACT
hfesten Stahl The ongoing trend towards miniaturization in various fields of material science requires the
1ochresten stahien capability to investigate the local mechanical properties of the concerned structures by
miniaturized mechanical experiments. Besides nanoindentation, miniaturized experiments
such as micro-compression, micro-tension, micro-bending, or micro-fracture tests were
vv Clarifv Fail employed frequently in recent times. A major challenge for these experiments is the
ssly Clarify Failure fabrication of specimens. Therefore, we present different approaches to prepare
miniaturized testing objects in a site specific way, using strategies that employ chemical
etching, broad beam ion milling, and focussed ion beam milling. Depending on the
Stahl required sample size and precision, the typical strategies for sample fabrication will be
tan 2013] W outlined, and the benefits and drawbacks of the techniques are discussed. Finally,
ISanalyse asser- applications of specimens produced by the different procedures are presented.
1. INTRODUCTION
It is well known that the strength of a material depends on two crucial factors, the
controlling internal material length scale, for example the grain size, dislocation spacing, or
precipitate spacing [1-4], and/or the sample dimension itself [5-8]. In the first case, the
microstructural features hinder the motion of dislocations, while in the latter case the free
surface of the sample: (i) limits the size of the dislocation sources that fit into the
specimen, or (ii) permits dislocations to leave the specimen through the free surface.
Furthermore, (iii) if the specimen is very small and the dislocation density is low, the
sample will statistically not contain a significant number of dislocations. For these
scenarios either the applied stress that is needed to operate a dislocation source,
essentially based on the Orowan stress required to bow a dislocation [9], or the lack of
dislocation sources to be activated, lead to higher stress for plastic deformation of objects
with reduced dimensions.
The miniaturization of components and devices concerns several fields of application, for
example microelectronics, medical applications, telecommunication, and mobility. For the
sake of simplicity, we will limit the general considerations to microelectronics. Due to the
ongoing miniaturization, typical conducting lines in microelectronics applications are
nowadays in the micrometer and sub-micrometer regime, with a continuing trend to further
reduction. This increases the demand of thermal, mechanical and electronic load bearing
capability of the used materials and requires the development of new material systems
