Effect of surface structure on the interfacial adhesion of polymeric adhesive in the fabrication of optical waveguide devices

In contrast to inorganic materials, electro-optic (EO) polymers are very attractive for optical devices due to their many advantages. Typical polymeric epoxy adhesive as a cladding material for optical waveguides, also offering integrate-able photonic devices to satisfy a significant industry need. The main critical issue of epoxy adhesive in this application is adhesion strength. High adhesion strength is a critical parameter of multi layer interconnections that fragile to shocks encountered during fabrication, handling and lifetime. The strength of the adhesive joints mainly depends on the surface structure or surface roughness that controls the state of the adhesion. Therefore continuous effort is paying to improve the adhesion. The aims of this paper are to study and understand the influence of surface structure on the interfacial adhesion of polymeric adhesive. A systematic investigation is carried out to study the interfacial adhesion on different type of substrate structure, such as pure silicon, silica on silicon & thin metal layer on silicon. From this study, it can be suggested that a thin layer of silica or metal film can be used to improve the adhesion of the polymer with the substrate for the fabrication of photonic devices