An edge bead removal device for a spin coater apparatus and methods of edge bead removal that overcome the deficiencies of conventional edge bead removal techniques. The edge bead removal device includes a coater cup and a head situated within the coater cup proximate to a peripheral edge of a substrate. The head is movable in a radial direction relative to an azimuthal axis of a rotatable substrate support inside the coater cup. The position of the head relative to a rim of the peripheral edge is mapped using an optical sensor. When the substrate support rotates the substrate and the head is used to dispense edge bead removal chemical, the radial position of the head is adjusted, as guided by the map, relative to the azimuthal axis to maintain a constant gap between the head and the substrate's peripheral rim.