Impact of DSA process variations on electrical performance of DSA-formed vias

DSA-formed vias

At SPIE Advanced Lithography Conference, world-leading nanoelectronics research center imec will present electrical results of DSA (directed self-assembly)-formed vias, gaining insight in the impact of DSA processing variations on electrical readout. The results accelerate learning towards implementation of DSA for via patterning at the N7 technology node and beyond.

DSA processes with cylinder-forming block copolymers (BCP) have gained attention for contact hole shrink applications with improved contact hole roughness, and for their potential to increase the contact hole density that is obtained with optical lithography. R&D efforts have focused on optimizing the process to obtain (pre-pattern) templates resulting in straight profiles after the DSA process, on increasing the feature density and on maximizing the open hole yield after pattern transfer. However, knowledge on electrical results from such DSA-based shrink processes is scarce.

Over recent years, imec has developed a templated grapho-epitaxy DSA flow for contact hole shrink and multiplication. Imec has applied this DSA flow to a short-loop test vehicle based on its 28nm node technology. Through testing the electrical performance of the DSA-formed vias, imec determined the via chain resistance as a function of process conditions including template dimension and BCP film thickness. Among a set of process conditions, increasing via chain resistance is observed with decreasing via CD (critical dimension). SEM images indicate high-quality via filling after metallization. The learning is now being applied to DSA via patterning in imec’s N7 technology.

Imec’s research into advanced patterning is performed in cooperation with imec’s core and strategic IC manufacturing partners including Samsung, Micron, Intel, Toshiba-Sandisk, SK Hynix, TSMC, GlobalFoundries and material and equipment makers.


About imec

Imec performs world-leading research in nanoelectronics. Imec leverages its scientific knowledge with the innovative power of its global partnerships in ICT, healthcare and energy. Imec delivers industry-relevant technology solutions. In a unique high-tech environment, its international top talent is committed to providing the building blocks for a better life in a sustainable society. Imec is headquartered in Leuven, Belgium, and has offices in Belgium, the Netherlands, Taiwan, US, China, India and Japan. Its staff of more than 2,300 people includes almost 700 industrial residents and guest researchers. In 2014, imec’s revenue (P&L) totaled 363 million euro. Further information on imec can be found at Stay up to date about what’s happening at imec with the monthly imec magazine, available for tablets and smartphones (as an app for iOS and Android), or via the website