Functional underlayers and primers improving dose and defectivity after lithography and after etching

In this work we present two “use cases” of assist layers which integrate one or more functionalities to improve the performance of photoresist in Extreme Ultraviolet (EUV) lithography. In the first case, functional underlayer and middle layer reduce dose and defectivity of dense contact hole patterning by chemically amplified resist. In the second case the patterning of dense lines/spaces arrays of pitch 24 nm by metal oxide resist is improved by using thin spin-on primer on Si-based deposited underlayers. Functional spin on layers and primers bring the advantage of fast and convenient way to improve performance in EUV lithography, do not require additional hardware and can be integrated into the existing manufacturing flow with minimal effort for chipmakers.