Prakt. Met. Sonderband 47 (2015) 3
Anwendung der Rontgenmikroskopie in der Mikroelektronik und
Energietechnik
Application of X-ray microscopy in microelectronics and energy tech-
nology
Ehrenfried Zschech** Jürgen Gluch?, Sven Niese***, Anna Lewandowska®“ M. Jürgen Wolf“, Lars
Röntzsch“, Markus Löffler®
* Fraunhofer Institute for Ceramics Technologies and Systems (IKTS), 01109 Dresden, Germany
b Dresden Center for Nanoanalysis (DCN) and Center for Advancing Electronics Dresden (cfaed), Technische Universi-
tät Dresden, 01062 Dresden, Germany
¢ Warsaw University of Technology, Faculty of Materials Science and Engineering, 02-507 Warsaw, Poland
4 Fraunhofer Institute for Reliability and Microsystems (IZM), ASSID, 01468 Moritzburg, Germany
¢ Fraunhofer Institute for Manufacturing Technology and Advanced Materials (IFAM), Branch Lab Dresden, 01277
Dresden, Germany
“now with: AXO DRESDEN GmbH, 01237 Dresden, Germany
I Introduction
X-rays are universally valued for their ability to penetrate opaque objects. X-ray imaging and X-ray
tomography are the techniques of choice for two- or three-dimensional inspection of medium and
small sized objects and objects’ interiors with resolutions well beyond that of light microscopy. The
techniques reveal structural characteristics and flaws, such as cracks and pores, or compositional
features. There is a wide variety of applications in materials science, life science, geoscience and
microelectronics - from biological objects such as insects or bones, over structural materials like
alloys - to image the distribution of precipitates - and composites - to image the components and the
quality of interfaces - micro- and nano-scaled technical systems such as interconnects in microelec-
tronic products and miniaturized sensors.
X-ray microscopy and X-ray tomography provide non-destructive imaging capabilities on speci-
mens across a range of length scales, observing features with sizes spanning from millimetres to
micrometers to several 10 nanometers. In this paper, we will focus on lab-based X-ray microscopy
and nano X-ray computed tomography (XCT) of objects with sub-100nm resolution.
2 X-ray microscopy
X-ray imaging is based on the different absorption of X-rays depending on their path length through
the transmitted material and the energy-dependent absorption properties of the material. Classically,
high resolution imaging is achieved by magnification techniques. Practically, the achievable resolu-
tion is in the range of one micron. For resolutions significantly better than 1 pm, and particularly for
sub-100nm resolution, the projection technique has to be replaced by an imaging technique. To im-
age an object using X-rays, a microscope setup with focusing lenses is needed. There exist two dif-
ferent approaches: refractive lenses or diffractive lenses. Diffractive optics such as state-of-the-art
Fresnel zone plates (FZP) consist of alternating regions of materials with different refractive indices
