Patterning process for semiconductor using Directed Self-Assembly

Directed self-assembly (DSA) process of block copolymers (BCPs) has been considered as a candidate for sub-20nm contact patterning. In recent years the semiconductor manufacturers have been interested in use DSA in production. DSA is based on the intrinsic property of the BCPs which is phase-separation in the molecular scale, but significant problems remain for device application. Process time, high process temperature, defect, and CD distribution make the using of DSA difficult in mass production. One of the most considered problems for DSA is the CD Distribution. A guide material for grapho-epitaxy DSA process requires resistance against high temperature and solvent. We use negative tone develop (NTD) photoresist (PR) guide for simple process and thermal resistance, and additional treatment for resistance against high temperature and solvent. The CD distribution of DSA is highly related to the phase separation itself. In order to get better performance, the polymer chains should have sufficient mobility under heating above their glass temperature. Therefore, film thickness and molecular weight of BCPs are very important parameters for CD distribution of DSA process. From the results, it is proven that guide materials, film thickness of BCPs, and molecular weight of BCPs are significant parameter in order to improve CD distribution of DSA patterns.