Understanding etch properties of advanced chemically amplified EUV resist

Abstract

Extreme ultraviolet (EUV) lithography technology empowers integrated circuit industry to mass produce chips with smaller pitches and higher density. Along with EUV tool advancement, significant progress has also been made in the development and advancement of EUV chemically amplified resist (CAR) materials, which allows for the improvement of resolution, line edge roughness, and sensitivity (RLS) trade-off. The scarce number of EUV photons has triggered the development of resist material with high absorption at 13.5 nm. However, a review of open literature reveals very limited reports on the effect of high EUV absorption elements on etch properties of advanced EUV resist. To ensure Moore’s Law continues to move forward, further resist performance improvement is required. In this regard, stochastic defects originating from photon shot noise, materials, and processing variabilities present a unique challenge for the extension of CAR platform for the patterning of smaller nodes. Notably, less attention has been paid to defects formed during the etching process used for pattern transfer. In this paper, we report on the relationship between resist make-up and etch properties. In particular, the effect of incorporation of EUV high absorbing elements are examined. New resist material design strategies for continuous improvement of EUV CAR lithographic performance will be discussed.