NEEDS – Nanoelektronik Entwurf für 3D-Systems is a research project funded by the German Federal Ministry of Education and Science (BMBF).
The increasing pace of miniaturisation of (nano-) electronic systems and the ability to integrate diverse components like sensors and actors enabled more and more application fields for these systems. Continuous improvements of the design processes as well as the application of new technology enlarge the fields of application of these systems.
Due to ever increasing requirements particular functionalities are no longer implemented on separate chips. Instead complete systems are implemented in a single chip, so-called System-on-a-chip (SoC). Integration of new and heterogeneous functionality heavily increases the production cost of this SoCs. The possibility to stack dies was considered only rarely or not at all. Three dimensional, stacked electronic circuits – also called 3D-chips – allows new and additional possibilities for optimising such complex and heterogeneous systems, compared to conventional 2D systems. For example:
The compact layout also brings some drawbacks. It also creates new challenges. Building in three dimensions offers new degrees of freedom, which has to be used in an efficient way. One problem however is the thermal behaviour of 3D chips. In a common 2D design, head can dissipate via a head-spreader mounted on top of the chip. In a 3D system this is not possible. Therefore thermal aspects must be considered during the development. Commonly used tools and methods are specialised for the development of two dimensional chips. For 3D chips new techniques are required that are able to analyse and optimise the thermal behaviour already during the design phase.