November 7, 2012
imec at ESTC2012
In the past decade, interconnect
and packaging technologies have become key enablers for advanced
microelectronic systems. The world
witnessed an amazing growth of smart phones and tablet devices, but also in
other domains, microelectronic technologies are becoming pervasive.
Eric Beyne, imec
medical field, electronic devices will be instrumental to control the
increasing cost of health care, and in the field of energy, one sees an urgent
need for increasing power efficiency. Consequently, we expect a strong increase
in the microelectronic content in many applications. .
IEEE-CPMT societyĺs Electronics System Integration
Technology Conference (ESTC) is the premier European event that brings together
researchers, innovators, decision-makers, technologists, businesses, and
professional associations working on interconnect and packaging technologies
for electronic system integration. The latest developments in assembly
and interconnection technology are presented and discussed there. This event is
also strongly supported by the IMAPS Europe professional society.
Jan Vanfleteren, imec - UGent
industry has consolidated to adopting the 3D-stacked IC approach as the most
performing and economically most viable 3D technology for mainstream consumer
and high performance applications, In order to optimize performance and cost of
such applications, imec worked on scaling TSV diameter and chip-to-chip
interconnect pitch. For this we investigated novel techniques and materials enabling
to electrically isolate scaled TSVs and to metalize them. In the field of microbump,
we identified and resolved specific integration and reliability challenges that
pertain to the extreme scaling of the micro bump pitch.
Imec also explored the
scaling potential of alternative, direct metal chip-to-chip interconnections. We
also evaluated extended device thinning and handling of ultra thin wafers and dies
and we researched and proposed solutions for challenges related to the
integration of an extreme thinning process onto microbumped device wafers. Also
3D-stack packaging is an integral part of the work performed by imec and its
partners in order to enable scaled 3D-systems to become reality.
Another development that is being
addressed at ESTC is the ultrathin chip package (UTCP). In this technology bare
Si or III-V semiconductor chips are thinned down from their initial thickness
of a few hundreds of microns to a thickness of 20 to 30Ám. Subsequently they
are embedded in polyimide sheets, produced from spin-on precursors. The
resulting package is as thin as 60 to 100Ám.
electronic appliances are rigid, or at most mechanically flexible. In the
future, many electronic assemblies on rigid substrates will be replaced by
mechanically flexible or even stretchable alternatives. This is a consequence
of the ambient intelligence vision where the user carries along more and more
electronic systems near the body, on or even inside the body.
must be light weight, take the shape of the object in which they are
integrated, and follow all complex movements of these objects, explaining the
need for elasticity. Typical examples are implants, intelligent textile,
portable electronic equipment (e.g. mobile phones), robotics, car electronics,
A number of flexible
technologies is currently under investigation. For implantable devices,
biocompatibility of the package is an important aspect, and for intelligent
textile applications, washability of the circuits is also under investigation.
A first option is based on components with standard rigid packages that are
connected with elastic electrical interconnections.
Another option contains electrical
interconnections of meander shaped metal tracks, which under deformation act as
2-dimensional springs. And finally, a technology with circuits embedded in an
elastic material like PDMS (silicone) or poly-urethane (PU) is under
development. Stretchability of up to 100% (1-time stretching) of these circuits
has been demonstrated.
together with the university of Ghent, presented an ultra-thin, flexible chip
with bendable and stretchable interconnects integrated into a package that
adapts dynamically to curving and bending surfaces. A commercially available
microcontroller was thinned down to 30Ám, preserving the electrical performance
and functionality. This die was then embedded in a slim polyimide package
Next, this ultrathin chip was integrated with stretchable
electrical wiring. These were realized by patterning polyimide-supported
meandering horseshoe-shaped wires, a technology developed and optimized at the
lab. Last, the package was embedded in an elastomeric substrate, e.g.
polydimethylsiloxane (PDMS). In this substrate, the conductors behave as two
dimensional springs, enabling greater flexibility while preserving
Eric Beyne, imec & Jan Vanfleteren, imec - UGent