In situ Dissolution Analysis of Ultrathin Extreme Ultraviolet Resists

Abstract

With extreme ultraviolet (EUV) resists reaching resolution capabilities beyond the 20 nm half-pitch line and space patterns, a trend has emerged in applying ultrathin resists (film thickness less than 60 nm) to compensate for possible issues in resolution-limiting pattern collapse and line width roughness, among other aspects. Thus, a clear understanding of the pattern mechanisms of resists at these extreme conditions is necessary. This paper focuses on the pattern formation characteristics of various EUV resist platforms for ultrathin films during dissolution by using in situ high-speed atomic force microscopy in liquid. As a result, it was observed that, regardless of the resist platform, there is a decrease in the size of the “dissolution clusters” at ultrathin conditions. Such fundamental information on ultrathin resist films may provide possible pointers to further extend the potential of EUV resists for achieving higher resolution limits and minimal line width roughness.