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1. INTRODUCTION
Directed self-assembly (DSA) lithography is one of the promising next generation lithography. There are mainly 2 requirements for next generation lithography. One is smaller size lithography for logic and DRAM etc.. Another is 3D lithography for 3D semiconductor devices. Regarding DSA lithography, wide-range DSA to expand applicable patterning size was studied. However, there are not well known a potential of 3D lithography; deep pattern of directed self-assembly and deep RIE on Si devices. This paper describes xylan high-chi block copolymer and its wider range of 3D patterning size.
2. EXPERIMENTAL RESULTS AND DISCUSSION
A structure model of xylan block copolymer for wide-range DSA lithography is proposed. It is composed of A and B part in hydrophobic part and C and D part in hydrophilic part. Part D has xylan structure. The xylan block copolymers were synthesized and dissolved in PGMEA. Metal contamination was removed. Then, they were spin-coated on a substrate with guide pattern, annealed and carried out dry development using RIE on 300 mm wafer. Directed self-assembly patterns were evaluated by SEM.
In our experimental results, half pitch 8.3 nm of L/S pattern and CD 51 nm of hexagonal hole pattern were obtained. According to these results, xylan block copolymer is suitable for wide-range DSA.
Spin coated thickness of xylan block copolymer were evaluated. From 50 nm to 1.3 μm of thickness was realized and micro phase separation was confirmed. These results suggest xylan block copolymer has a possibility of wider thickness range of micro-phase separation.
Si deep RIE of xylan block copolymer was carried out. Silicon depth was 300 nm. It seems that xylan block copolymer is suitable for 3D semiconductor lithography.
3. SUMMARY
It was confirmed xylan block copolymer is suitable for 3D patterning size on directed self-assembly lithography. It has a big potential for wider application of not only 2D but also 3D semiconductor devices.
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