Abstract
In immersion lithography the optical path between the lens element and the photoresist is currently water. Defects have been identified as a major roadblock for the introduction of immersion lithography to real device manufacturing. To address these immersion specific defect issues we have developed a novel additive approach for controlling the resist surface and it's interaction with water.[1] These additives have been designed to segregate within the resist film and migrate to the resist surface. Due to the high local concentration of these additives at the resist/water interface they create a very hydrophobic surface and allow control of surface properties. Data will be presented on this novel concept, illustrating the control of leaching and resist surface hydrophobicity. The use of this new technique allows control of leaching, resist surface contact angles and immersion specific defects.
As critical dimensions (CDs) in the semiconductor industry shrink, pattern collapse becomes a problem. We classify pattern collapse into three classes: adhesion failure, pattern strength failure and pattern film loss failure, and relate these to the capillary forces which drive failure. In this paper, the correlation of PCM with Ψ (carbon heteroatom ratio) of polymer composition, resist profile, PEB temperature and time are discussed. Finally, mechanistic understanding of pattern failure and subsequent correlations gives us the tools to design advanced resist with excellent PCM.
