Materials Challenges and Alternatives for Advanced Photolithographic Patterning: From 193 to 157 nm and Beyond

Abstract

AbstractIn the last decade, major advances in fabricating electronic devices have placed increasing demands on microlithography, the technology used to generate today's integrated circuits. Within the next few years, a new form of lithography will be required that routinely produces features of less than 0.1 μ. As the exposing wavelength of light decreases to facilitate higher resolution imaging, the opacity of traditional materials precludes their use; and major research efforts to develop alternate materials are underway. Through understanding of materials structure and its relationship to device process requirements and performance, cycloolefin based polymers provide for sub-0.1 μm imaging capability using 193 nm exposure. Alicyclic monomers such as norbornene are readily copolymerized with other units to afford a wide range of alternative matrices that exhibit transparency at the exposing wavelength and aqueous base solubility. Further reduction in imaging wavelength necessitates renewed research to define alternative materials platforms. Materials transparency is the key issue to be addressed for 157 nm or EUV lithography. Novel polymer architectures including fluorinated polymers will be required to effect sufficient transparency coupled with requisite solubility, sensitivity, contrast etching resistance, shelf life and purity. Each of these issues will be discussed from the perspective of polymer materials chemistry.