Effect of spin coating on the interfacial adhesion of epoxy adhesive on silicon substrate for the fabrication of polymer optical waveguide

Due to the complexity of common spin coating solutions, it is very interesting to consider and study how mixed solutions behave due to spinning. An investigation was carried out on a silicon substrate to study the effects of spin coating on the adhesion behavior of the epoxy adhesive. Adhesion strength was evaluated by a shear button test. Shear button was made of adhesive of 10 μm height with 100 μm by 100 μm patterned on silicon wafer substrate using lithography process. Shear button test was carried out with 6 mil shear tips at a shear speed of 100 μm/s. Adhesion strength of spin coated epoxy adhesive was measured at various location of the substrate. It varies at different locations of the spin-coated substrate. At the center of the substrate it is higher than the other locations due to greater cross-linking density. Correlation of the spinning with adhesion was also studied through the detailed investigation of the fracture surfaces under optical microscopy. It was also proposed to use solvents, which will allow a greater part of the thinning behavior to occur without significant changes in the fluid properties during the spinning process.