Fabtrication of Surface Plasmon Biosensors in CYTOP

Abstract

This thesis describes work carried out on the research, development and implementation of new processes for the fabrication of surface plasmon waveguide biosensors. Fabrication of surface plasmon resonance (SPR) based waveguides embedded in a thick CYTOP cladding with the incorporation of fluidic channels was achieved with improved quality and operability compared to previous attempts. The fabrication flow was modified in key areas including lithography for feature definition, gold evaporation and the upper cladding deposition procedure. The combined result yielded devices with sharper resolution of waveguides, gold surfaces with minimal aberrations, reduced surface roughness and minimization of waveguide deformation due to reduction of solvent diffusion into the lower cladding. The fabricated waveguides consisted of a thin, 35 nm, patterned gold film, embedded in a thick, 18 µm, CYTOP fluoroploymer cladding. The gold devices were exposed by O2 plasma etching through the upper cladding to form fluidic channels for the facilitation of flow of an index matched sensing medium. Optical and physical characterization of devices revealed structures of significantly improved quality over previous attempts, rendering the platform competitive for biosensing applications.