Abstract
As exposure wavelengths continue to decrease, the use of conventional single layer resist (SLR) materials is becoming increasingly more difficult. Since most organic materials absorb at wavelengths below 200 nm, it becomes problematic to create polymers with sufficient transparency to serve as SLR resins. This paper is focused on a novel approach to top surface imaging, termed surface monolayer initiated polymerization (SMIP), in which a reactive monolayer is exposed and patterned. This pattern is subsequently amplified by surface polymerization to produce patterned polymeric features that can serve as an etch barrier. In particular, the reactive monolayer is exposed to patterned radiation (UV, x-ray, e-beam, etc.) that deactivates the monolayer in the exposed areas. The substrate is then heated or exposed to radiation in the presence of a monomer, resulting in activation of the monolayer in the unexposed areas and polymerization of patterned polymer structures. Thus, in this type of process the imaging properties of the monolayer system and the etch resistance of the polymer film formed are completely decoupled. This paper focuses on recent results intended for characterizing the exposure kinetics of a radical initiator compound, 4,4'-Azobis-(4-cyanopentanoic acid-(3'-chlorodimethylsilyl) allylic ester), used as a SMIP monolayer. X-ray photoelectron spectroscopy (XPS) has been used to measure the kinetics of the DUV (248 nm) exposure reaction in this monolayer. Examples of simple patterning tests using this approach are also presented.
