Three-dimensional integrated circuits (3D ICs) contain multiple layers of active device chiplets and have the potential to improve signal transfer and the overall performance of a microelectronic systems, while saving energy. Dr Takafumi Fukushima is an Associate Professor based in the Department of Mechanical Systems Engineering, Tohoku University, Japan, whose research revolves around 3D/heterogeneous/flexibel integration technologies. Within the Department Fukushima focuses on self-assembly technologies. 'Self-assembly is the process by which an organised structure spontaneously forms from individual components, as a result of specific, local interactions among the components,' he explains. One of these is advanced DSA. This process enables ultrafine-pitch interconnect formation through the simple coating and heating of nanocomposites with block co-polymers and metal compounds/nanoparticles. 'DSA is a type of directed assembly which utilises the nano-phase separation of block co-polymers to create ultrafine lines, space and hole patterns, facilitating more accurate control of the feature shapes,' Fukushima outlines. 'Conventional DSA with the block co-polymers is an alternative way to photo-patterning with photoresists that are spin-on photosensitive materials to photolithographically form fine patterns and traditionally used in semiconductor industry.' Through his advanced DSA Fukushima is able to make both ultrafine patterns as well as form lateral and vertical interconnections with nanocomposites based on non-photolithographic methodology.