Improvement study of Mitsui SOC materials for multilayer lithography process

In this report, we will describe the progress of our new SOC material development for the underlayer. In the advanced patterning technology such as EUV lithography, the etching resistance and the adhesive property with a middle layer will be key requirements as well as the planarization. We designed new polymers for SOC material that were improved the etching resistance toward next generation patterning technology on the basis of Ohnishi parameter as a guideline of the polymer design. The etching resistance of our newly developed polymers were about 1.7 times and 1.5 times stronger than the polymer A we reported previously and the PHS or novolac. The adhesive property was evaluated by measuring water contact angle and the water contact angle of our newly developed polymers were similar to the novolac. This result indicated that the developed polymer showed similar hydrophilicity to the novolac with keeping higher O₂ etching resistance than novolac.