"The business unit "Micro and Nano Electronics / Back-End of Line" focuses on the following main fields of activity:

• Materials, processes, and technologies for advanced bach-end of line schemes,
  
• Process technology for 3D integration micro and nano systems,
• Modeling and simulation of processes, equipments, as well as complete interconnect systems,
• Characterization and reliability assessment, starting from BEOL components towards complete chip-package interactionsn including 3D integrated systems.

The Back-End of Line (BEOL) comprises all process steps starting from contact level till complete wafer processing prior to electrical testing (in other words: the entire interconnect system including passivation). Depending on the specific product (high performance/ low power/ generic), significant changes in the Back-End of Line have been implemented within the past years due to ongoing downscaling. While transistors become faster as their dimension shrink, the interconnect system is limiting this gain in speed, because its RC product rises. Thus, signal delay time increases. Appropriate materials can reduce resistance and capacitance of the interconnect system and consequently compensate for the losses. While the past decade was characterized by the introduction of copper and low-k-dielectrics, future challenges require holistic approaches as well as novel concepts. In that context, 3-dimensional integrated ICs and microsystems are promising candidates to further increase integration density as well as extend functionality. Thus, intership connections realized by Through Silicon Vias (TSV) are required and become part of the interconnect system. Beyond this, the later stacking concept needs to be considered because of its strong interaction with the interconnect system. At Fraunhofer ENAS close meshed interrelations between technology, material science, modeling and simulation, as well as characterization and reliability assessment have been established to cope today’s and further challenges.

The business unit "Micro- and Nanoelectronics/Bach-End of Line" is mainly driven by the core competences "Interconnect Technologies" and "Reliability of Components and Systems". Moreover, additional input comes from the core competences "System Integration Technologies", "Silicon Based Technologies for Micro and Nano Systems", and "Design and Test of Components and Systems".