Development of high-chi directed self-assembly process based on key learning from PS-b-PMMA system

In contrast to the technology relying on the reaction of photosensitive materials with light, directed self-assembly (DSA) uses the microphase separation of block copolymer (BCP) to define the pattern. Because of the inherently different nature of pattern formation, L/S pattern with the pitch around 30 nm has been demonstrated with DSA of PS-b-PMMA system without suffering from typical challenges of EUV resist pattern. Instead, the major challenge was to control DSA-specific defects, which is the result of the non-ideal assembly of BCP, within timescale acceptable for high volume manufacturing. Holistic optimization of material and process conditions enables low and stable defectivity of DSA process with improved throughput. In this paper, the key learning from PS-b-PMMA system will be thoroughly reviewed. And the strategy to leverage this learning for developing high-chi DSA system will be discussed.