Eungnak Han

Extending resolution limits of EUV resist materials

Extreme ultraviolet lithography (EUVL) technology continues to progress and remains a viable candidate for next generation lithography1, which drives the need for EUV resists capable of high resolution with high sensitivity and low LWR. While chemically amplified resists (CARs) have demonstrated the ability to pattern 12nm half-pitch features2, pattern collapse continues to limit their ultimate resolution. We have taken multiple approaches to extend resist capabilities past these limits. Recent results in pattern collapse mitigation using a resist encapsulation and etch back strategy will be discussed. We continue to investigate EUV patterning of semi-inorganic resists to simultaneously increase EUV photon absorption and extend mechanical strength beyond CAR capabilities. The limitations of metal oxide-based nanoparticle photoresists have been investigated, and have provided key insights to further understanding the mechanism of this class of materials.

Material readiness for generation 2 directed self-assembly (DSA) < 24nm pitch

The self-assembling behavior of thermally annealed PS-b-PMMA block copolymer derivatives (GEN2 BCPs) was evaluated using a substrate modified by a random copolymer, commonly called a ‘brush’. Similar to PS-b-PMMA, surface modification using the random copolymer brush served as an effective technique for controlling the domain orientation of the GEN2 BCP and yielded aligned features with pitches below 24nm. Non-preferential and weakly preferential random copolymers were also defined and applied to DSA using a graphoepitaxial approach. Finally, a Dry Development Rinse Process (DDRP)[1] was tested as a method to prevent pattern collapse and improve pattern transfer for GEN2 BCPs.